The -d0.1 (a.k.a. -d0) debugging switch previously prevented sendmail from forking and detaching itself, but that function has been moved to the -d99.100 debugging switch. The -d0.1 debugging switch now just tells sendmail to print information about its version:

Version 8.8.4
Compiled with:   LOG MATCHGECOS NAMED_BIND NDBM NEWDB NETINET NETUNIX
                 NIS
SYSTEM IDENTITY (after readcf):
            (short domain name) $w = here
        (canonical domain name) $j = here.US.EDU
               (subdomain name) $m = US.EDU
                    (node name) $k = here

The Version is the current version of sendmail. Note that for Sun the number may look like SMI-8.7.5.

The Compiled with: lists the compile-time definitions that where specified when sendmail is compiled. All the available definitions are listed in Table 18.3 in Section 18.8, "Alphabetized Reference".

The SYSTEM IDENTITY shows the value assigned to four important macros. The meaning of each macro is contained in Table 31.7 in Section 31.10, "Alphabetized Reference".

The -d0.4 debugging switch tells sendmail to print several additional lines of information:

Version 8.8.4
Compiled with:   LOG MATCHGECOS NAMED_BIND NDBM NEWDB NETINET NETUNIX
                 NIS
canonical name: here.US.EDU                            additional
 UUCP nodename: here                                   additional
        a.k.a.: [123.45.67.89]                         additional
============ SYSTEM IDENTITY (after readcf) ============
            (short domain name) $w = here
        (canonical domain name) $j = here.US.EDU
               (subdomain name) $m = US.EDU
                    (node name) $k = here
========================================================

To find the canonical name of the local host, sendmail calls gethostname(). If that call fails, the name localhost is used. The hostname is then looked up with the internal routine sm_gethostbyname(), which gathers additional information (such as other names and addresses for the machine) and fixes several bugs in some operating system's versions of the gethostby... routines. Next the canonical name for the local host is looked up. For operating systems that normally support switched services, the name is looked up as specified. For systems that specify switched services in the configuration file's ServiceSwitchFile option (see Section 34.8.61, ServiceSwitchFile), switched services are not used because the configuration file has not been read yet. (This canonicalization process can be traced with the -61.10 debugging switch.) If the canonical is found and that name contains a dot, sendmail saves the part of the name to the right of the leftmost dot as the domain name in the $m macro (see Section 31.10.24, $m). It also appends the part of the name to the left of the leftmost dot to the class w (see Section 32.5.8, $=w). If the canonical name doesn't contain a dot, the $m macro is undefined, and the whole name is appended to the class w.

In addition, sendmail also sets the $k macro (see Section 31.10.21, $k) to be the correct UUCP name for the machine. It uses uname(3), if available, to find that name (see Section 18.8.51, TRUST-POPEN); otherwise, it uses the same strategy as for class w above.

Then sendmail lists any other names or addresses (this latter in square brackets) that it found. If it finds any, it prints the name prefixed by a.k.a.: and appends each to the class w. The aliases listed are only those found using gethostbyname(3). To see each entry as it is added to the class w, use the -d37.8 debugging switch.

Finally, sendmail scans the network hardware to find any other names associated with interfaces. If the ioctl(2) call to get that information fails, the -d0.4 debugging switch causes sendmail to print that failure:

SIOGIFCONF failed:  reason here

If any are found, each is printed with an a.k.a.: prefix and added to the class macro w.

The -d0.10 debugging switch causes sendmail to print all the operating system specific definitions that were used to compile your specific version of sendmail. This output prints after the "Compiled with:" information described above:

OS Defines: HASFLOCK HASGETUSERSHELL HASINITGROUPS HASLSTAT
                HASSETREUID HASSETSID HASSETVBUF HASUNAME IDENTPROTO
                IP_SRCROUTE
Kernel symbols: /vmunix
   Config file: /etc/sendmail.cf
  Proc Id file: /etc/sendmail.pid

The OS Defines are described in Table 18.3 in Section 18.8. Most are automatically determined during compilation; others are specified in Makefile.

The Kernel symbols is the name of file that is accessed to determine the load average. It is automatically defined correctly when conf.c is compiled. The location of the configuration file and the process identifier file are defined in the Makefile and conf.h in the sendmail source (see Section 18.8.34, PATH...).

The -d0.15 debugging switch causes sendmail to display how it interpreted its delivery agent definitions. The clarity and completeness of the delivery agent information vary with the version of sendmail. See the =M rule-testing command (Section 38.4.2, "Show Delivery Agents with =M") for an example of this output.

When sendmail scans the network hardware to find other names for the local host, it uses only those names that are new. Each new name was printed by the -d0.4 debugging switch above. To see every name that sendmail finds, new and old alike, use the -d0.20 debugging switch:

128.32.201.55                                        already found
127.0.0.1                                            found new
        a.k.a.: [127.0.0.1]

Ordinarily, if the UUCP name for the local host cannot be found (if uname(3) fails), sendmail silently uses the leftmost component of the canonical name as the UUCP name. To see whether uname(3) failed - and, if so why - you can use the -d0.22 debugging switch:

uname failed (reason for failure here)

The -d0.40 debugging switch causes sendmail to announce that it is about to scan for network interfaces:

scanning for interface specific names, ifc_len=64
        a.k.a.: [127.0.0.1]

The ifc_len is the size in bytes of the configuration list returned by the kernel.

The -d0.44 debugging switch causes sendmail to prefix certain lists of strings that it prints with the address in memory of each string and an equal sign. With this debugging level, part of the output produced by the -d21.12 debugging switch would look like this:

--- rule fails
---trying rule:
        0009ec68=@
        0009ec78=$*
--- rule fails

This debugging level can be useful to the programmer who wishes to modify the sendmail source. It might, for example, be helpful in designing more efficient string storage.

The -d0.90 debugging switch causes sendmail to display its internal interpretations of the first 10 rewriting rules it took from the configuration file. The rule sets are printed in numeric order, rather than in the order in which they appeared in the configuration file. The rewriting rules are printed under each rule set (but these are in the order in which they appeared in the configuration file). Rule sets that are declared but lack rewriting rules are not printed. Note that defined macros in the RHS are expanded (the value used) when the configuration file is parsed. Also note that expressions like $+ may be printed as control characters (e.g., ^A) under older versions of sendmail.

The preferred way to view individual rule sets is with the -bt rule-testing mode's =S command (see Section 38.4.1, "Show Rules in a Rule Set with =S").

Although there are many kinds of information that one might like to trace about the sender of an email message, sendmail provides the means to trace only one of them. The -d1.1 (a.k.a. -d1) debugging switch causes sendmail to print its interpretation of whom the message is from (the name of the sender as it was used in the envelope):

From person = "sender"

Here, sender is the user portion of the mail address of the sender. This output is most useful when combined with the -f command-line switch (which sets the name of the sender from the command line; see Section 36.7.21, -f and -r).

The -d1.5 debugging switch causes additional information about the sender to be printed. That output looks like this:

main: QDONTSEND output of printaddr() here (see Section 37.3.1, "The Output Produced by printaddr()")

The QDONTSEND means that the sender is not a recipient and so should not get a copy of the message. That is followed by the output of the printaddr() routine.

Ordinarily, sendmail exits silently when it is done (unless an error causes an error message to be printed). The -d2.1 (a.k.a. -d2) debugging switch causes sendmail to print three useful values when it exits. The message it prints looks like this:

====finis: stat num e_id=qid e_flags=flags

The num is the final value of the sendmail program's global ExitStat variable. It is usually updated to contain the latest error value as defined in <sysexits.h>. See Section 36.5, "sendmail's exit() Status" for a detailed description of the possible exit values.

The qid is either the queue identifier (such as SAA24069) or the NOQUEUE if the message was never assigned an identifier (such as if it was never queued).

The flags is a hexadecimal representation of the possible envelope flags followed by a text representation of those flags in angle brackets with the leading EF_ removed, for example,

201003<OLDSTYLE,INQUEUE,GLOBALERRS,HAS_DF>

These are the envelope flags that were in effect with the current envelope when sendmail exited. The possible values are shown in Table 37.3.

Table 37.3: Hexadecimal Envelope Flags

Text	Hex	Description
EF_OLDSTYLE	0000001	Use spaces (not commas) in headers
EF_INQUEUE	0000002	This message is fully queued
EF_NO_BODY_RETN	0000004	Omit message body on error
EF_CLRQUEUE	0000008	Disk copy is no longer needed
EF_SENDRECEIPT	0000010	Send a return receipt
EF_FATALERRS	0000020	Fatal errors occurred
EF_KEEPQUEUE	0000040	Keep queue files always
EF_RESPONSE	0000080	This is an error or return receipt
EF_RESENT	0000100	This message is being forwarded
EF_VRFYONLY	0000200	Verify only (don't expand aliases)
EF_WARNING	0000400	Warning message has been sent
EF_QUEUERUN	0000800	This envelope is from queue
EF_GLOBALERRS	0001000	Treat errors as global
EF_PM_NOTIFY	0002000	Send return mail to postmaster
EF_METOO	0004000	Send to me too
EF_LOGSENDER	0008000	Need to log the sender
EF_NORECEIPT	0010000	Suppress all return-receipts
EF_HAS8BIT	0020000	At least one 8-bit character in body
EF_NL_NOT_EOL	0040000	Don't accept raw newline as end-of-line
EF_CRLF_NOT_EOL	0080000	Don't accept carriage-return/line-feed as end-of-line
EF_RET_PARAM	0100000	SMTP RCPT command had RET argument
EF_HAS_DF	0200000	Set when df file is instantiated
EF_IS_MIME	0400000	Really is a MIME message
EF_DONT_MIME	0800000	This message is not MIME-able

For example, if the message were fully queued and required a DSN return receipt, the flags would print as

e_flags=12<INQUEUE,SENDRECEIPT>

Note that this line of output is also produced by the -d13.1, -d40.3, and -d50.1 debugging switches but under different circumstances.

The -d2.9 debugging switch tells sendmail to display the properties of each open file descriptor. That output is produced by the dumpfd() routine, and each line of output is for a single file descriptor:

num: fl=flags mode=mode type stats

Here, the num is the number of the open file descriptor. Note that descriptors 0, 1, and 2 are usually tied to the standard input, output, and error output.

The flags is a hexadecimal representation of the state flags associated with a file descriptor. F_GETFL is used with ioctl(2) to fetch each, and all are described in <sys/fcntlcom.h>.

The mode is printed in octal and is the st_mode associated with an fstat(2) of the file descriptor. The type examines the file type portion of the st_mode and prints SOCK for a socket, CHR: for a character special device, BLK: for a block special device, FIFO: for a first-in-first-out file, DIR: for a directory, LNK: for a symbolic link, and nothing otherwise (e.g., nothing if it is a file).

The stats are printed for all but the socket. They look like this:

dev=major/minor ino=inum nlink=nlink u/gid=uid/gid size=bytes

Here the dev= shows the major and minor device numbers for the device that the file descriptor is associated with. The inum is the inode number on the disk (if there is one) and nlink is the number of hard links to the file on disk. The uid/gid shows the user and group ownership associated with the file descriptor. The size is the number of bytes in a file, and 0 for almost everything else.

For a socket, the stats part of each line looks like this:

[addr]/port-> host

Here, addr is the IP address of the local end of the socket. If the connection is of type AF_INET, the port number of the connection is also shown as /port. The host is the hostname, as returned by getpeername(3), of the connecting host. If any of these cannot be found, the error string associated with errno is printed parenthetically in its place.

The -d7.9, -d40.9, and -d46.9 debugging switches also print a line like this for specific file descriptors. Also if sendmail is run with the -d10.100 switch, or if sendmail fails to open a tf queue file (see Section 23.2.6, "The Temporary qf Rewrite Image: tf"), or if sendmail exited because of too many open files, it will syslog all its open file descriptors within this format.

The sendmail program queues mail, rather than delivering it, if the load average (number of processes in the run queue) exceeds the value set by the QueueLA (x) option (see Section 34.8.50, QueueLA (x)). Exceeding that value also prevents messages that are already in the queue from being delivered (prevents a queue run). If the load average becomes higher than the value of the RefuseLA (X) option (see Section 34.8.54, RefuseLA (X)), sendmail rejects incoming SMTP connections until the load average drops.

The -d3.1 debugging switch (a.k.a. -d3) causes sendmail to print the load average found by its internal getla() routine each time that routine is called:

getla: la

Here, la is the current load average printed as an integer. If sendmail was compiled with LA_TYPE==LA_ZERO (see Section 18.8.14, LA-TYPE), the following will be printed to show that your sendmail binary completely lacks load averaging support:

getla: ZERO

The -d3.1 debugging switch also causes sendmail to print any errors it encounters while obtaining the load average.

getla: open(/dev/kmem): error

Here, /dev/kmem is the device that is used to access kernel memory. The error is the system error that caused the failure, such as "Permission denied" if sendmail is not properly sgid to the group kmem.

getla: nlist(unix): error

The nlist(3) function extracts a list of symbols from an executable binary (among them the symbol for the load average). The binary that it extracts is the kernel whose pathname is unix (such as /vmunix for SunOS 4.x). Here, the error is the reason nlist(3) failed. One possibility is that you booted from a nonstandard kernel name (such as /vmunix.new) and the expected file didn't exist:

getla: nlist(unix, la) ==> 0

If the expected kernel exists (unix) but the machine was booted from a different kernel, the symbol representing the load average may not be found. In that instance, la is the name of the kernel variable that sendmail was trying to find.

The load average that sendmail uses is averaged over the last minute. Internally, the kernel keeps track of three load averages. In addition to the last minute, it also tracks the last 5 and 15 minutes. The -d3.5 debugging switch causes V8 sendmail to print the load average over the last minute:

getla: averun = 1min

The -d3.15 debugging switch causes V8 sendmail to print all three load averages:

getla: averun = 1min, 5min, 15min

Here, the three load averages are printed either in integer or in floating point, depending on the setting of LA_TYPE (see Section 18.8.14).

The nlist(3) routine (described above) provides the offset into the kernel file where the value of the load average is found. The -d3.20 debugging switch causes that offset to be displayed:

getla: symbol address = offset

Here, the offset is printed in hexadecimal. The load average is read by seeking in the kernel file and reading it. If the seek or read fails, the -d3.1 debugging switch causes sendmail to print:

getla: seek or read: error

This can indicate a wrong or corrupted kernel image.

The internal routine shouldqueue() is called just before a mail message is delivered to recipients. That routine determines whether mail will be delivered or queued on the basis of the current load average and message priority. Upon entry it prints:

shouldqueue: CurrentLA=load, pri=priority

If the CurrentLA is less than the limit set by the QueueLA (x) option (see Section 34.8.50), sendmail prints:

FALSE (CurrentLA < QueueLA)

Then the calculation described in Section 34.8.49, QueueFactor (q) for the QueueFactor (q) option is performed using the pri priority. The result is printed as one of the following, where TRUE represents a zero result and FALSE represents a nonzero result:

TRUE (by calculation)
FALSE (by calculation)

The MinFreeBlocks (b) option (see Section 34.8.40, MinFreeBlocks (b)) defines the minimum number of disk blocks that must be reserved on the queue disk. If an incoming SMTP message will fill the disk beyond this minimum, the message is rejected.

The -d4.80 debugging switch [1] traces the enoughspace() routine in conf.c. That routine examines the disk space and allows or disallows incoming mail.

[1] No -d4.1 (a.k.a. -d4) information is available.

enoughspace: no threshold

This debugging output says that no limit was defined with the MinFreeBlocks (b) option.

enoughspace: bavail=haveblocks need=needblocks

This debugging output shows that the number of blocks free (available) on the disk is haveblocks and that the number of blocks required by incoming mail is needblocks. Note that haveblocks will always be -1 if sendmail was compiled with SFS_TYPE set to SFS_NONE (see Section 18.8.40, SFS-TYPE).

enoughspace failure: min=boption need=needblocks

If the required number of blocks (needblocks) exceeds the minimum reserved as defined by the MinFreeBlocks (b) option (boption), use of the disk is disallowed.

Throughout its many possible levels of forks and children, sendmail must keep track of timeouts - the maximum amount of time it should wait for an event to occur. For example, a child must not wait forever for an SMTP greeting message, because the program at the other end may never provide that message (because it died or is just too busy).

To keep track of which child should be notified at which time, sendmail maintains an internal queue of events. The sendmail program uses the SIGALARM signal and the alarm(2) system call to set the interval it waits to next check its queue of events for timeouts. That interval (called a tick) is the period of the timeout itself, or if the timeout is scheduled for the present or past, the interval is three seconds. The -d5.4 debugging switch [2] causes sendmail to print the current time whenever the queue of events is examined:

[2] There is no -d5.1 (a.k.a. -d5) information.

tick: now=time

Here, time is the current time in seconds as returned by time(2).

Events are set by the process (child or parent) that needs a timeout. The -d5.5 debugging switch causes sendmail to print the information that is used to set up for that timeout:

setevent: intvl=secs, for=timeo, func=addr, arg=pass, ev=evnt

The information is the timeout interval in seconds (secs), the time (now plus the interval) in seconds that the timeout will occur (timeo), the address in memory of the subroutine that will be called if a timeout occurs (addr), the argument to be passed to that subroutine (pass), and the address in memory of the C language structure that contains this information (evnt). The addr of the function to be called can be converted to a function name by running nm(1) on an unstripped binary of sendmail. For example, if the following output was produced by /usr/lib/sendmail:

setevent: intvl=3600, for=802463800, func=3ebc4, arg=0, ev=94b68

you could find the function name associated with the address 3ebc4 by running

%  nm /usr/lib/sendmail | grep 3ebc4
0003ebc4 t _readtimeout

Here, the result is the name readtimeout, which corresponds to the function readtimeout() in util.c.

When an event is cleared because a timeout was no longer needed, sendmail prints:

clrevent: ev=evnt

Here, evnt is the address in memory of the C language structure that stored the event information. This is the same as the last item printed by setevent above.

The -d5.6 debugging switch tells sendmail to print the following information when a timeout occurs:

tick: ev=evnt, func=addr, arg=pass, pid=pid

This shows that the event stored in the C language structure, whose address in memory is evnt, has timed out. The subroutine whose address in memory is addr will be called with an argument of pass. The process identification number of the parent process that asked for the timeout is shown as pid.

Mail can fail for a wide variety of reasons. The way that sendmail handles errors is determined by the setting of the ErrorMode (e) option (see Section 34.8.24, ErrorMode (e)) in the configuration file. The -d6.1 (a.k.a. -d6) debugging switch causes sendmail to print the error-handling mode that is in effect at the time it first begins to handle failed mail:

savemail, errorMode = char, id = qid, ExitStat = err
e_from=  output of printaddr() here (see Section 37.3.1)

Here, char is either: p for print errors; m for mail back errors; w for write back errors; e for special BERKnet processing; or q for "don't print anything" (all of which are described under the ErrorMode option in Section 34.8.24). The qid is the queue identifier (such as KAA15019). The err is the error that caused the message to fail (as defined in <sysexits.h>). And e_from= uses printaddr() to print details about the sender's address.

If the error-processing mode is m (for mail back) and the -d6.1 debugging switch is in effect, sendmail prints details about how the message is being returned to the sender:

***Return To Sender: msg=reason, depth=num, e=addr, returnq=
 output of printaddr() here (see Section 37.3.1)

Here, reason is a quoted string of text that explains why the mail failed. This may be an SMTP reply string. The num is zero for normal delivery and one for error delivery. The addr is the location in memory of the information about the current envelope. Finally, sendmail calls printaddr() to print the details of the queue of recipients (returnq=) for the current message.

The -d6.5 debugging switch tells sendmail to print the error state it was in when it finished processing the error that caused the message to fail:

state num

If num is 7 (successful delivery), nothing is printed. Otherwise, the above message is printed, and the value of num represents one of the states shown in Table 37.4.

Table 37.4: Error Handling States

State	Description
0	Report to sender's terminal
1	Mail back to sender
2	Messages have already been returned
3	Save in ~/dead.letter
4	Return to postmaster
5	Save in /usr/tmp/dead.letter
6	Leave the locked queue/transcript files
7	The message has been successfully delivered

The -d6.20 debugging switch tells sendmail to print additional information to that printed by -d6.1. Specifically, it prints, via printaddr(), the address information about the sender of returned mail:

***Return To Sender: msg=reason, depth=num, e=addr, returnq=
output of printaddr() here (see Section 37.3.1)
Sendq= output of printaddr() here

The sendmail program stores mail messages in its queue for a variety of reasons. For example, the SuperSafe (s) option (see Section 34.8.67, SuperSafe (s)) causes it to queue all messages just to be safe. Also, messages that cannot be delivered because of a temporary lack of resources (or for any correctable reason) are queued for later delivery.

Mail messages are stored in the queue in two parts. A data part contains the body of the message. An information part stores headers and other information about the message. The filenames of the two parts are identical but for the first two letters. A df begins the name of the data part, and a qf begins the name of the information part. A third type of queue file begins with the letters xf and is a "transcript" file that holds error messages produced during delivery.

To ensure that these filenames do not conflict with the names of files that may already be in the queue, sendmail uses the following pattern to create new names:

qfHAApid

Here, pid is the process identification number of the incarnation of sendmail that is trying to create the file. Because sendmail often fork(2)'s to process the queue, the pid is likely unique and therefore creates a unique name.

The H represents the current hour of the day (using a 24-hour clock) and prefixes the AA. It is constructed by adding the current hour to the letter A (thus 00:23 would produce A+0=A, while 15:45 would produce A+15=P). Although it is not recommended, the hour character can be useful in viewing the queue (with the -bp command-line switch) to observe the particular hours, if any, that messages tend to queue. The hour prefix does not increment.

If sendmail cannot create a file (because a file with that name already exists), it increments the rightmost A of the AA part of the name to a B and tries again. It continues this process, incrementing the right from A to Z and the left from A to ~ until it succeeds. If a unique name cannot be found, sendmail has failed in its attempt to queue the message. The last filename tried is:

qfH~Zpid

This name is unlikely to ever appear, because the clocking provides for over 1600 possible unique names. With some versions of sendmail, however, it may appear if the queue directory is not writable. For example, the -C command-line switch, when used by a normal user, might cause sendmail to give up its root privilege, thus causing this message to be printed.

The -d7.1 (a.k.a. -d7) debugging switch causes sendmail to print the portion of the queue name that is common to all the files that constitute a single queued message.

queuename: assigned id HAApid, env=addr

Here, sendmail prints the identifier portion of the filename (the HAA, or whatever letters succeeded, and the pid) that is common to the df, qf, and xf files. The addr is the address in memory of the C language structure that describes the envelope for the mail message that is queued.

The -d7.2 debugging switch tells sendmail to print the full filename of the file that it just created in the queue directory:

queuename: letterfHAApid

The first letter of the name is either d, q, or x. The pid is the process identification number of the sendmail process that created the file.

Once sendmail successfully opens its qf file, it has established the unique identifier. The -d7.9 debugging switch causes sendmail to dump the file-descriptor for that open file:

lockfd= output of dumpfd() here (see Section 37.5.13)

The -d7.20 debugging switch causes sendmail to print each filename that it is attempting to try as it clocks the AA in the name from AA to ~Z:

queuename: trying qfHAA16391
queuename: trying qfHAB16391
queuename: trying qfHAC16391
queuename: trying qfHAD16391
...  and so on

Name resolution is the process of determining a machine's IP address based on its fully qualified domain name. This is done by using the Domain Name System (DNS). The process that sendmail uses to resolve a name is described in Section 21.2, "How sendmail Uses DNS".

When sendmail finds that a hostname is really an MX (mail exchanger) record, it attempts to look up the A record for the host that handles mail receipt. That request may fail for a variety of reasons. If the -d8.1 (a.k.a. -d8) debugging switch is specified, sendmail produces the following message:

getmxrr: res_search(host) failed (errno=err, h_errno=herr)

Here, host is the hostname that was being looked up, err is the system error number (if any) from <errno.h>, and herr is the resolver specific error from <netdb.h> as shown in Table 37.5.

Table 37.5: Resolver Errors from netdb.h

Value	Mnemonic	Description
1	HOST_NOT_FOUND	Host not found (authoritative answer returned)
2	TRY_AGAIN	Nonauthoritative server not found or server failure
3	NO_RECOVERY	Nonrecoverable errors and refusals
4	NO_DATA	Valid name but no record of requested type

The routine dns_getcanonname() in domain.c of the sendmail source converts a hostname to a fully qualified domain name. This routine is called only if DNS is used to look up hostnames, as determined by the ResolverOptions (I) option (see Section 34.8.55, ResolverOptions (I)) and the ServiceSwitchFile option (see Section 34.8.61). If it is, dns_getcanonname() can be called from two places: during startup to get the values for $w, $j, and $m (see Section 37.5.2) or when a host is looked up via the $[ and $] canonify-operators (see Section 28.6.6, "Canonicalize Hostname: $[ and $]").

The -d8.2 debugging switch shows the hostname before it is fully qualified with this call:

dns_getcanonname(host, flag)

If the flag is nonzero, calls to the getmxrr() routine (which looks up MX records) are also traced. On entry to that routine, sendmail will print:

getmxrr(host, droplocalhost=bool)

The host is the hostname that MX records are being looked up for. The bool, if nonzero, means that all MX records that are less preferred than the local host (as determined by $=w) will be discarded. If zero, they will be retained.

The -d8.2 debugging switch also causes sendmail to show the result of processing the ResolverOptions (I) option's settings (see Section 34.8.55) while reading the configuration file:

_res.options = hex, HasWildcardMX = 1 or 0

The hex is a hexadecimal representation of the state structure's options variable as described in <resolv.h>. The value of HasWildcardMX is determined by its prefix (+ or -) when listed with the ResolverOptions (I) option.

If a hostname is dropped because bool (above) is nonzero, the -d8.3 switch causes sendmail to print the following:

found localhost (host) in MX list, pref=pref

The host is the hostname that is being dropped. The pref is the preference associated with the MX record.

The -d8.5 debugging switch causes the getcanonname(3) routine to print the hostname it is trying to fully qualify. It shows the name with the local domain appended without the local domain appended, and at each step in between. Each try is printed as:

getcanonname: trying host.domain (type)

Here, the type is the type of lookup and is either ANY, A, or MX.

The -d8.7 debugging switch causes sendmail to print a yes or no response to each of the "trying" lines printed by -8.5. Yes means that the host could successfully be fully canonicalized. A yes answer prints just this:

YES

If the host could not be canonicalized, a more complex answer is printed:

NO: errno=err, h_errno=herr

The err is the system error number (if any) from <errno.h>, and herr is the resolver specific error from <netdb.h> as shown in Table 37.5.

The -d8.8 debugging switch causes the resolver library to be put into debugging mode (if that was mode was included when that library was compiled). The ResolverOptions (I) option (see Section 34.8.55) +DEBUG also turns on this debugging mode. But be aware that turning on +DEBUG will cause a large number of screens full of output to be produced by the resolver library for every DNS lookup.

If the name server returns an answer to an MX lookup, and if the answer is not an MX record or an error, sendmail will skip that host. The -d8.8 debugging switch (or the resolver library being in debug mode) then causes sendmail to print the following:

unexpected answer type wrongtype, size bytes

The wrongtype is an integer that can be found in <arpa/nameser.h>.

Internally, the resolver library (libresolv.a) stores host domain names in compressed form (for transmission efficiency). We won't cover the nature of that compression. For our purposes it is sufficient to know that the sendmail program calls dn_skipname(3) from the resolver library to skip past the compressed part of a host domain name. That call should never fail, but if it does, the -d8.20 debugging switch causes sendmail to print:

qdcount failure (questions)

The questions is a count of the number of queries made.

The -d9.1 (a.k.a. -d9) debugging switch can be used to watch sendmail convert hostnames and addresses into canonical form. This is done by watching the host_map_lookup() function with -d9.1. First the hostname is looked up in the symbol table. If it exists there and if it is marked as a valid canonical entry, sendmail prints

host_map_lookup(host) => CACHE canon

Here, the name host was found in the symbol table. The value returned was a valid canonical name. If host had not been found, the canon would have printed as NULL.

If sendmail is running in defer-delivery mode (see the DeliveryMode (d) option in Section 34.8.16, DeliveryMode (d)), it will skip looking up the hostname further. This is done because dial-on-demand connections should not be brought up merely to perform unnecessary DNS lookups. When sendmail skips further lookups, it prints:

host_map_lookup(host) => DEFERRED

If the name is not in the symbol table, it is looked up with the getcanonname() function. First sendmail prints:

host_map_lookup(host) =>

with no trailing newline. Then, if the canonical name is returned by getcanonname(), that returned name is printed. Otherwise, FAIL is printed. If sendmail is compiled with NAMED_BIND defined for DNS support (see Section 18.8.23, NAMED-BIND), the FAIL is followed by the resolver specific error (herr) from <netdb.h>:

host_map_lookup(host) => herr

The -d9 debugging switch is also used to display identd(8) queries. When a network connection is made from a remote host to the local host, the local sendmail uses the RFC1413 identification protocol to query the remote host for the name of the user who instantiated the connection. The result of that query is printed as:

getauthinfo: result

Here, result is two pieces of information: an address composed of the username, an @, and the real name of the remote host and the IP address of that host:

getauthinfo: [email protected] [123.45.67.8]

If the query fails, nothing is printed.

The above information is not provided by the remote host in that clear form. Instead, sendmail needs to parse the needed information from a raw reply. The -d9.3 debugging switch causes the raw reply to be printed:

getauthinfo:  got raw_reply

The -d9.10 debugging switch causes sendmail to display its outgoing RFC1413 query:

getauthinfo: sent query

Here, the outgoing query is composed of two numbers: the TCP port on the remote machine where its RFC1413 server is running, followed by a dot and the local port number for the original connection.

When sendmail is about to deliver a mail message, it has already resolved three pieces of information: which delivery agent to use, the name of the host that receives the message, and the name of one or more recipients for that message. The -d10.1 (a.k.a. -d10) debugging switch tells sendmail to display information about the recipient to whom it is about to deliver:

-deliver, id=mid, mailer=num, host=`hname', first user=`uname'

Here, mid is the queue message identifier (such as PAA08463). The num is the number of the delivery agent selected. Delivery agent numbers can be displayed by using the -d0.15 debugging switch. The hname is the name of the host that receives delivery. The uname is the name of the first of possibly many users who receive the mail message. The uname can be either a single name such as joe or a full forwarding address such as [email protected].

When sendmail attempts delivery, it may be delivering to multiple recipients. It stores its list of recipients internally as a linked list of C language structures, each of which holds information that is specific to each recipient address. The -d10.1 debugging switch also causes sendmail to print that information using the printaddr() routine:

send to output of printaddr() here (see Section 37.3.1)

Every recipient address may have a controlling user associated with it (see Section 23.9.2, C line). The -d10.2 causes sendmail to dump the address of the controlling user using the printaddr() routine:

ctladdr= output of printaddr() here (see Section 37.3.1)

If the MeToo (m) option (see Section 34.8.39, MeToo (m)) is set to false, the -d10.5 debugging switch tells sendmail to dump the address that won't receive (the QDONTSEND) the mail message.

deliver: QDONTSEND output of printaddr() here (see Section 37.3.1)

The -d10.100 debugging switch tells sendmail to dump all its file descriptors just before it is about to attempt delivery.

The -d11.1 (a.k.a. -d11) debugging switch is used to trace message delivery. For each delivery agent the following is printed:

openmailer: argv

Here, argv is the A= array for the delivery agent, with macros expanded and printed.

The status of remote hosts is cached internally. Before connecting to a remote host, sendmail checks its cache to see whether that host is down. If it is, it skips connecting to that host. If the -d11.1 debugging switch is also specified, the status of the down host is printed as:

openmailer: output of mci_dump() here

The output of mci_dump() looks like this:

MCI@memaddr: flags=mci_flags<flag,flag,...>, 
errno=mci_errno, herrno=mci_herrno, exitstat=mci_exitstat, state=mci_state,
pid=mci_pid, maxsize=mci_maxsize, phase=mci_phase, mailer=mci_mailer,
host=mci_host, lastuse=mci_lastuse

The meaning of each mci_ item in the above output is described in Table 37.6.

Table 37.6: The Meaning of the MCI Structure Items

Name	What prints
mci_memaddr	The address in memory of this C language structure
mci_flags	The flag bits in hexadecimal (see Table 37.7)
mci_errno	The error number of the last connection
mci_herrno	The DNS h_errno of the last lookup
mci_exitstat	The <sysexits.h> exit status of last connection
mci_state	The current SMTP state (see Table 37.16)
mci_maxsize	The maximum size message the host will accept
mci_pid	The PID of the child process
mci_phase	SMTP phase (string) such as "client greeting" (or NULL)
mci_mailer	The (text) name of the delivery agent (or NULL)
mci_host	The host's name (or NULL)
mci_lastuse	Last usage time in ctime(3) format

Table 37.7 shows what the individual flag bits in mci_flags mean, and the human-readable flags text that corresponds to each bit. Those text items are shown with the leading source MCIF_ prefix removed.

Table 37.7: The Meaning of mci_flags Hexadecimal Values

Value	Name	Meaning
0001	VALID	This entry is valid
0002	TEMP	Don't cache this connection
0004	CACHED	This connection currently in open cache
0008	ESMTP	This host speaks ESMTP
0010	EXPN	EXPN command supported
0020	SIZE	SIZE option supported
0040	8BITMIME	BODY=8BITMIME supported
0080	7BIT	Strip this message to 7 bits
0100	MULTSTAT	MAIL11V3: handles MULT status
0200	INHEADER	Currently outputting header
0400	CVT8TO7	Convert from 8 to 7 bits
0800	DSN	DSN extension supported
1000	8BITOK	OK to send 8-bit characters
2000	CVT7TO8	Convert from 7 to 8 bits
4000	INMIME	Currently reading MIME header

After checking to see whether the host is down, sendmail attempts to connect to it for network SMTP mail. If that connect fails, the -d11.1 debugging switch causes the following to be printed:

openmailer: makeconnection => stat=exitstatus, errno=errno

Here, exitstatus is a numerical representation of the reason for the failure as documented in <sysexits.h>, and errno is the system-level reason for the error, as documented in <errno.h>.

Other errors, such as failure to establish a pipe(2), or failure to fork(2), causes the following to be printed:

openmailer: NULL

This message (although it contains no information) signals that a more descriptive error message was logged with syslog(3) (see Section 26.1, "Logging with syslog").

To perform delivery, sendmail often has to set its uid to something other than root's. The logic behind that process is described in Section 24.2.2. The -d11.2 debugging switch tells sendmail to print the real and effective uid's that it is running under during delivery.

openmailer: running as r/euid=ruid/euid

Also, the -d11.2 debugging switch causes sendmail to print any error response that may be produced by a delivery agent:

giveresponse: stat=status, e->e_message=what

Here, status is the error that caused delivery to fail (or succeed if it is 0) as defined in <sysexits.h>. The what is either the error message produced by the delivery agent or "<NULL>" if the delivery agent was silent.

Execution of a delivery agent can take place in any of a sequence of directories as defined by the D= delivery agent equate (see Section 30.4.3, D=). The -d11.20 debugging switch causes each directory to be printed as it is tried:

openmailer: trydir dir

Here, dir is the name of the directory that sendmail is about to chdir(2) into.

In the SMTP RCPT command, sendmail is required to express the recipient's address relative to the local host. For domain addresses, this simply means that the address should be RFC822-compliant.

The -d12.1 (a.k.a. -d12) debugging switch causes sendmail to print the address as it appeared before it was made relative:

remotename(addr)

If the addr is for the sender or recipient and is being processed from a queue file, then nothing more is printed, and the addr is processed by rule set 3. If the delivery agent for the recipient has the F=C flag set (see Section 30.8.15, F=C) and the recipient address lacks a domain part, then the domain of the sender is appended, and the result is processed by rule set 3 again. Sender/recipient-specific rule sets are then applied (1 and S= for the sender, or 2 and R= for the recipient). Next, rule set 4 is applied, and any macros in the result are expanded. Finally, the fully qualified and relative address is printed as:

remotename => `addr'

The -d13 (a.k.a. -d13) debugging switch causes sendmail to display information about the recipients of each mail message as it is being delivered. The -d13.1 debugging switch tells sendmail to print the mode of delivery and then the recipient information:

SENDALL: mode dmode, id=mid, e_from output of printaddr() here (see Section 37.3.1)
        e_flags = envelope flags here
        sendqueue:
output of printaddr() here (see Section 37.3.1)

Here, dmode is one of those shown in Table 37.8. The mid is the queue message identifier (such as PAA08463). The address of the sender, e_from, is dumped by using the printaddr() routine. Then the envelope flags, e_flags, are dumped as described in Table 37.3. Next, information about all the recipients (sendqueue:) is printed by using the printaddr() routine.

Table 37.8: Delivery Modes Used by sendall()

Mode	Description
i	Interactive delivery
j	Deliver w/o queueing (obsolete as of V8)
b	Deliver in background
q	Queue, don't deliver
d	Defer, queue w/o DNS lookups
v	Verify only (used internally)

Finally, the -d13.1 debugging switch causes sendmail to print a message every time it splits an envelope in two:

sendall: split orig into new

Here, orig is the original queue message identifier for the original envelope (such as PAA08463) and new is the identifier for the new envelope, the near identical clone of the first. Envelopes need to split if they have different owners.

The -d13.5 debugging switch is used to display addresses to which mail should not be delivered. One such address is that of the sender of the cloned envelope after a split:

sendall(split): QDONTSEND output of printaddr() here (see Section 37.3.1)

Another is the sender address (unless the MeToo (m) option, see Section 34.8.39, is set):

sendall: QDONTSEND output of printaddr() here (see Section 37.3.1)

Finally, senders who are the owner- of mailing lists (see Section 25.3, "Defining a Mailing List Owner") should not have mail sent to them.

sendall(owner): QDONTSEND output of printaddr() here (see Section 37.3.1)

This latter sender address is derived by a call to setsender(), which can be separately viewed with the -d45 debugging switch.

The -d13.10 debugging switch causes sendmail to print the following upon entering its internal sendenvelope() routine:

sendenvelope(ident) e_flags=hex

The ident is either the queue identifier (such as SAA24069) or the [NOQUEUE] if the message was never assigned an identifier (such as if it was never queued). The e_flags are dumped in hexadecimal as described in Table 37.3.

The sendmail program's delivery mode (as initially set with the DeliveryMode (d) option; see Section 34.8.16) can change during delivery for a complex series of reasons. The -d13.20 debugging switch causes the final delivery mode to be displayed:

sendall: final mode = char

Here, char is the one of the characters that can be specified for the DeliveryMode (d) option.

If, after all recipient addresses are checked, none are left to be delivered to (everyone of them was either dropped or queued), and if the DeliveryMode (d) option (see Section 34.8.16) is neither q, d, nor v, the -d13.29 debugging switch will cause sendmail to print:

No deliveries: auto-queuing

The process of creating another envelope for another sender is called "splitting the envelope." The -d13.30 debugging switch causes sendmail to show its initial scanning of the send queue to count the number of envelopes (including split envelopes) that will be needed.

Checking output of printaddr() here (see Section 37.3.1)

Then, depending on the result, each owner will have one of the following printed:

... QDONTSEND
    ... QBADADDR|QQUEUEUP
    ... expensive
    ... deliverable

The Q flags are described under the output of printaddr() in Section 37.3.1.

Some programs require that addresses in a list of recipients be separated from each other by space characters. This is called an "old-style" address. RFC822 requires that addressees be separated from each other with comma characters.

The -d14.2 [3] debugging switch tells sendmail to show each header line that may need spaces converted to commas.

[3] There is no -d14.1 information.

commaize(header: list)

Here, header is the caption part of a header line, such as From:. The list is a sequence of one or more addresses.

When sendmail runs in daemon mode, it opens a socket on a port, then listens on that socket for incoming SMTP connections. The -d15.1 (a.k.a. -d15) debugging switch prints information about both of those steps. Note that -d15.1 should usually be combined with -d99.100, or some output may be lost.

Before the socket is opened, sendmail prints the following:

getrequests: port 0xportno

This shows that the port numbered portno (printed in hexadecimal notation) is used to open the socket. If that open fails, sendmail syslog(3)'s one of the following messages at LOG_CRIT and exits:

getrequests: problem creating SMTP socket

If the open succeeds, sendmail attempts to bind to that socket. If it cannot bind, it syslogs the following message at LOG_CRIT and exits:

getrequests: can't bind socket

After it binds, sendmail goes into a loop in which it listens for and handles incoming SMTP requests. If the listen fails, sendmail syslog(3)'s the following message at LOG_CRIT and exits:

getrequests: cannot listen

If sendmail starts to listen successfully, this -d15.1 debugging switch causes it to print the number of the socket on which it is listening:

getrequests: sockno

This shows that sendmail is then listening on the socket whose file descriptor is sockno.

In daemon mode, sendmail waits for an incoming SMTP connection. When that connection is made, sendmail forks, and the child processes the connection from that point on. The -d15.2 debugging switch causes sendmail to print a message that confirms that it is performing this fork. Note that -d15.2 should usually be combined with -d99.100, or some output may be lost:

getrequests: forking (fd = sock)

Here, sock is the value of the socket being used for the connection. The -d15.2 debugging switch also causes a message to be printed when the child process exits:

getreq: returning (normal server)
getreq: returning (null server)

Here, failure of the connection to be validated (see Section 22.4.1, "Accept/Reject Connections via libwrap.a" and Section 29.10.3, "The check_relay Rule Set"), causes null server to be printed. A successful connection causes normal server to be printed.

Finally, the -d15.2 debugging switch causes the following to be printed every time opendaemonsocket() routine is called:

opendaemonsocket()

On kernels that support this feature, the -d15.101 debugging switch turns on kernel debugging for the socket that is opened to handle an incoming SMTP connection. Debugging is turned off when the socket is closed at the end of receipt of the message. The debugging information gathered can be viewed with the trpt(8) program.

When mail messages are sent to a site that can be reached via a TCP/IP connection, the -d16.1 (a.k.a. -d16) debugging switch causes sendmail to print one of the following messages when it is about to make the connection:

makeconnection: (host [NULLADDR])             null address
makeconnection: (host [0])                    no address family
makeconnection: (host [[UNIX: path]])         AF_UNIX family
makeconnection: (host [ip address])           AF_INET family
makeconnection: (host [[LINK: name]])         AF_LINK family
makeconnection: (host [Family num:0xbytes])   unknown family

Here, host is the name of the host to which the connection is made. The form of the address information differs depending on the address family. If the connection can be successfully made, the -d16.1 debugging switch then causes sendmail to print:

makeconnection: fd=sock

Here, sock is the socket descriptor that was issued for use with the socket connection.

If the DialDelay option (see Section 34.8.17, DialDelay) is nonzero and the connection fails, sendmail will sleep DialDelay seconds and try again. If the -d16.1 debugging switch is also specified, sendmail will print:

Connect failed (error message); trying again...

Here, error message describes the reason for the initial failure.

If there is more than one address for a host, sendmail will try each in turn until one connects successfully. The -d16.1 debugging switch causes the following to be printed for each failure:

Connect failed (error message); trying new address....

Note that the -d16 debugging switch should usually be combined with the -d99.100 debugging switch, or some output may be lost.

See -d15.101. The only difference here is that debugging is turned on for the outgoing socket.

When sendmail readies to deliver mail to a remote host, it looks up that host using DNS to find Mail Exchanger (MX) records. The -d17.1 (a.k.a. -d17) debugging switch causes V8 sendmail to print the following:

hostsignature(host) = records

Here, host is the host that was looked up with DNS. The records is a colon-delimited list of MX records for that host. That list might contain only the original hostname if no MX records were found.

MX records have preferences. Delivery is to the record with the lowest preference first, then to each higher preference, in turn, until a delivery succeeds. When two or more preferences are equal, V8 sendmail randomizes them so that they are tried in a different order. The order is the same each time, so this is really a pseudo-randomization (actually a hash function).

The -d17.9 debugging switch causes sendmail to print the following each time it randomizes:

mxrand(host) = hash

This shows that the MX records for host have been given a hash value of hash.

The process of transmitting (or receiving) a mail message using the SMTP protocol requires sendmail to send replies as its side of the dialogue. The -d18.1 (a.k.a. -d18) debugging switch causes sendmail to print each reply that it sends. It prefixes what it prints with three right angle brackets:

>>> RCPT To: [email protected]

Note that this is the same output as produced with the -v command-line switch (see Section 36.7.41, -v).

The -d18.1 debugging switch also causes the following message to be printed to the standard output if the file descriptor for the connection is NULL:

smtpmessage: NULL mci_out

Prior to opening the connection, the -d18.1 debugging switch causes sendmail to print:

smtpinit output of mci_dump() here

Finally, the -d18.1 debugging switch causes sendmail to print:

reply

Each time it enters its reply() routine.

The -d18.2 debugging switch causes sendmail to show processing of the SMTP MAIL From: command that the local machine will send.

smtpmailfrom: CurHost=host

Here, host is the name of the current host that sendmail is dealing with.

The -d18.100 debugging switch causes sendmail to pause(2) after a read error when processing the SMTP dialog. The administrator can then use ps(8) and gcore(8) to produce a core dump, which can then be examined with a debugger to determine the reason for the read error.

Under Extended SMTP (ESMTP) the MAIL and RCPT command can be followed by other optional parameters. The -d19.1 (a.k.a. -d19) debugging switch displays those parameters. We discuss the MAIL command first, then the RCPT command.

37.5.65.1 Show MAIL parameters

The sendmail program recognizes four parameters that can follow the address in the SMTP MAIL command: [4] SIZE, which specifies the size in bytes of the incoming message; BODY, which specifies the nature of the message body (8bitmime or 7bit); ENVID, which is used to propagate a sender-specific unique identifier for the envelope; and RET, which specifies whether or not to return the message body on an error return.

[4] SIZE is defined in RFC1653, BODY is defined in RFC1652, and ENVID and RET are defined in RFC1891.

The -d19.1 debugging switch causes sendmail to print the parameters it received:

MAIL: got arg param="value"

The param is one of the parameters shown above. The nature of the value depends on the param

The value for SIZE is a positive integer. If SIZE lacks a value, this error is issued:

501 SIZE requires a value

When multiple, illegal SIZE values are specified, the last is the one whose value is used.

The value for BODY is a case-insensitive string. It can either be 8bitmime or 7bit. If BODY lacks a value, the following error is issued:

501 BODY requires a value

If BODY has neither of the approved strings as its value, the following error is issued:

501 Unknown BODY type bad string here

When multiple, illegal BODY values are specified, the last is the one whose value is used.

The value for ENVID is a special envelope identifier. It is composed of ASCII characters in the range ! through ~, excepting + and =. Characters outside that range and those two excepted characters are replaced with a + followed by a hexadecimal representation of the character's value (there must be exactly two hexadecimal digits). If ENVID lacks a value, the following error is issued:

501 ENVID requires a value

If the text of the value is not as described above, the following error is issued:

501 Syntax error in ENVID parameter value

If more than one ENVID specified is for a given envelope, the second results in this error:

501 Duplicate ENVID parameter

The value for RET is one of two possible case-insensitive strings: hdrs tells sendmail to return only the headers of a bounced mail message; full tells sendmail to return the headers and body of a bounced mail message. If no string is present, the following error is issued:

501 RET requires a value

If a string is present but is something other than hdrs or full, the following is printed:

501 Bad argument bad string here

If more than one RET is specified for a given envelope, the following error is printed:

501 Duplicate RET parameter

If the parameter is not SIZE, BODY, ENVID, or RET, the following error is issued:

501 param parameter unrecognized

37.5.65.2 Show RCPT parameters

The sendmail program recognizes two parameters that can follow the address in the SMTP RCPT command: NOTIFY, which specifies when to notify the sender; and ORCPT, which specifies the original recipient's address.

The -d19.1 debugging switch causes sendmail to print the parameters it received:

RCPT: got arg param="value"

The param is one of the parameters shown above. The nature of the value depends on the param

The value for NOTIFY is either NEVER or a comma-separated list composed of SUCCESS, which means to notify the sender upon final delivery that the message was successfully delivered; FAILURE, which means to notify the sender if the message cannot be delivered; and DELAY, which means to notify the sender if the message is delayed. If there is no value, the following error is issued:

501 NOTIFY requires a value

If a value is present but it is not one of the words shown above, the following error is issued:

501 Bad argument \"bad value here\"  to NOTIFY

Multiple, illegal NOTIFY parameters in an envelope cause the subsequent values to be logically OR'd together.

The value for ORCPT is an address followed by a semicolon, then an address that is encoded in the same way as the envelope identifier described for ENVID above. If that value is missing, the following error message is issued:

501 ORCPT requires a value

If the value is syntactically wrong (i.e., if the value does not have a valid address following the semicolon), this error message is issued:

501 Syntax error in ORCPT parameter value

If multiple ORCPT values are specified, the second one results in this error:

501 Duplicate ORCPT parameter

The -d20.1 (a.k.a. -d20) debugging switch causes sendmail to print each recipient address before it is rewritten by rule sets 3 and 0:

-parseaddr(addr)

Here, addr is the recipient address before it is rewritten and before any aliasing has been performed on it.

The -d20.1 debugging switch also causes sendmail to print information about problems that may exist in recipient addresses. If an address contains any control character that is not an isspace(3) character, sendmail prints the following message and skips that address:

parseaddr->bad address

If an address is empty (that is, if it is composed entirely of an RFC822-style comment), sendmail prints the following and skips that address:

parseaddr->NULL

After the recipient address has been rewritten by rule sets 3 and 0, and if a delivery agent was successfully selected, sendmail prints the result using the printaddr() routine.

Note that -d21 can be used to watch the rule sets parse the address, and -d24 can be used to watch the resulting tokens being pasted back together.

The -d21.1 (a.k.a. -d21) debugging switch causes sendmail to print each step that it takes in rewriting addresses with rules. The -d21.1 debugging switch causes output to be produced that is identical to the output produced by the -bt command-line switch (see Section 38.1, "Overview"):

rewrite: rule set num   input: addr
rewrite: rule set num returns: addr

Here, num is the rule-set number, and addr is, first, the address (workspace) before rewriting and, second, the address after rewriting.

Because rules are recursive by nature, they can sometimes cause infinite loops (see Section 28.6.2, "Rewrite Once Prefix: $:"). When a rule loops more than 100 times, the following error is issued:

Infinite loop in rule set num, rule rnum

If the -d21.1 debugging switch was also invoked the above error is followed by:

workspace: state of rewritten address so far, here

The -d21.2 debugging switch tells sendmail to show the current value of any deferred-expansion macro (one that was declared with the $& prefix). Each such macro that is encountered in processing a rule prints as:

rewrite: LHS $&char => "value"
rewrite: RHS $&char => "value"

The char is the single-character name of the macro, and the value is its current value. If that particular macro lacks a value, it will print as (NULL). The LHS refers to the left-hand side of the rule, and the RHS corresponds to the right-hand side. Deferred-expansion macros are described in Section 31.5.3, "Use Value as Is with $&".

The -d21.3 debugging switch causes sendmail to print the rule-set number of each rule set called as a subroutine. Rule sets are called as subroutines by using the $> rewrite-operator in the RHS of rules (see Section 28.6.4, "Rewrite Through Another Rule Set: $>set"). The output produced looks like this:

---callsubr rset

Here, rset is the text that was interpreted as the number of the rule set, rather than the numeric value. If the number in the configuration file was a symbolic name, then that symbolic name is printed. (See Section 28.6.4 for more details about the $> rewrite-operator.)

If the LHS of a rule matches the workspace, the workspace is rewritten by the RHS of that rule. The -d21.4 debugging switch causes sendmail to print the result of a successful rewrite:

rewritten as: addr

Note that the rewritten address (addr) may be the result of rewriting by a subroutine call.

If the LHS of a rule fails to match the workspace, the -d21.10 debugging switch causes sendmail to print:

--- rule fails

If the LHS of a rule matches the workspace, the -d21.12 debugging switch causes sendmail to print:

--- rule matches

The -d21.12 debugging switch also causes the LHS of each rule to be printed before it is tried:

---trying rule: lhs

Remember that rules are pre-expanded when the configuration file is read. As a consequence, defined macros appear as their values in the lhs, rather than in their $letter form.

The -d21.15 debugging switch causes sendmail to print each replacement that is the result of a $digit rewrite-operator in the RHS:

$digit: hex=token ...

Here, $digit is followed by one or more hex=token pairs. The hex is the address in memory of the token, and the token is the token from the LHS that is being copied into the workspace. This output can run to many screens.

In addition to the rewriting information shown by the debugging switches mentioned above, the -d21.35 debugging switch also shows each and every attempt by the LHS to match the workspace. Each comparison is printed like this:

ap=workspace rp=operator

Here, ap (for address part) indicates the token in the workspace that the rule is currently trying to match. The rp (for rule part) is the operator or token at this point in the LHS that is trying to match the workspace. Note that the workspace is a single token from the workspace, and the operator is a single operator or token from the LHS of the current rule. A complete comparison of the LHS to the workspace can produce several lines of output for each rule. This output can be useful for understanding how the pattern-matching algorithm works.

The -d21.35 debugging switch also shows the index advancing to the next operator and what the corresponding state of the workspace is at that time.

ADVANCE rp=operator ap=workspace

This is useful for watching the left-hand side trying to find a match.

The -d21.36 debugging switch causes sendmail to print the following each time it finds a match for either the $= or $~ class-operator:

CLMATCH

The -d21.36 switch also shows how sendmail extends the token in the workspace and tries again, should a match for any operator fail. That is, for all operators (not just $= or $~), if the workspace contained usa.edu, sendmail would first look up usa, then usa., and finally usa.edu. Each such attempt prints as:

EXTEND rp=operator ap=workspace

If there is still no match, sendmail has to back up and try a different tack. In the case of usa.edu it would back up to the dot. For example, if it were trying $=X, the output would look like this:

BACKUP  rp=$=X, ap=.

Processing of rules requires that all addresses be divided into tokens. The -d22.1 (a.k.a. -d22) debugging switch causes sendmail to print the various steps it takes in tokenizing an address.

In addition to tokenizing, the prescan() routine also normalizes addresses. That is, it removes RFC822-style comments and recognizes quoted strings. Be aware that rules are also viewed as addresses and processed by prescan() when the configuration file is being read.

The -d22.1 debugging switch tells sendmail to complain if the first token in the address it is parsing turns out to be nothing

prescan: null leading token

This can happen if an address (or rule) contains only RFC822-style comments in parenthesis.

The -d22.11 debugging switch causes the address to be printed as it appears before any tokenizing or normalization:

prescan: addr

The -d22.12 debugging switch causes the address to be printed as it appears after all tokenizing and normalization:

prescan==> addr

The -d22.36 debugging switch causes each token to be printed when found:

tok=token

For the purpose of tokenizing, an address is viewed as a stream of characters. The process of tokenizing and normalizing is driven by a state machine that handles the stream one character at a time. For example, if the current character is @, sendmail sees that it has found both the start and end of a token and so resets its state to begin looking for a new token. But if the current character is a and sendmail is currently gathering a token, it knows that it should continue to gather. The use of a state machine enables sendmail to easily keep track of things such as the nesting level of angle brackets and whether or not a quoted string is present.

The -d22.101 debugging switch causes sendmail to output two lines of information. The first shows entry into a state (or continuation of a state):

c=char, s=state;

Here, char is the current character in the stream of characters that makes up the original address. The state is a two-digit octal representation of the current state. The first digit modifies the second and is a 2 (which means that this is a meta-character so don't pass it through), a 4 (which means to break the token at this character), or a 6 (which means both 2 and 4). The second digit indicates the state. The list of states and their meanings are shown in Table 37.9. The semicolon separates this output from the rest of the line that is printed below.

Table 37.9: States Used by parseaddr() to Tokenize Addresses

Decimal	Octal	Name	Description
0	00	OPR	A wildcard operator (such as $*)
1	01	ATM	An atom (text token)
2	02	QST	Inside a quoted string
3	03	SPC	Chewing up spaces
4	04	ONE	Pick up one character
5	04	ILL	Illegal character

The rest of the output produced by the -d22.101 debugging switch shows the state changing to a new state:

ns=nstate

Here, nstate is the new state number, printed in octal with a leading zero.

Note that the level 101 in -d22.101 means that this debugging output is for true experts only.

The -d24.4 debugging switch [5] tells sendmail to print a message upon its entry into the allocaddr() routine:

[5] There is no -d24.1 information.

allocaddr(flags=flags, paddr=paddr)

Here, the address in paddr will be copied into another address (not shown). The flags is a hexadecimal representation of the RF_ flags used by sendmail to communicate with some of its internal routines. The meanings of the bits in these flags are shown in Table 37.10.

Table 37.10: sendmail's Internal RF_ flags

Hex	Name	Description
000	RF_COPYNONE	Don't copy anything
001	RF_SENDERADDR	Set = sender address, otherwise recipient
002	RF_HEADERADDR	Set = header address, otherwise envelope
004	RF_CANONICAL	Strip RFC822 comments
008	RF_ADDDOMAIN	Okay to append a domain
010	RF_COPYPARSE	Copy parsed user and host
020	RF_COPYPADDR	Copy the print address

If RF_COPYPARSE is set in flags, the temporary strings for the host and user in the passed address (not shown) are allocated permanent storage in memory.

The -d24.5 debugging switch tells sendmail to print a message upon its entry into the buildaddr() routine.

buildaddr, flags=flags, tv=tokens

The buildaddr() routine takes an array of separate tokens and pastes them back together again. The flags are ORed together hexadecimal values as documented in Table 37.10. The RF_SENDERADDR and RF_HEADERADDR flags tell buildaddr() which rewriting rules to use in processing the address.

The array of tokens being assembled is printed on a single line, each separated from the other by a space.

The -d24.6 debugging switch tells sendmail to print the result of buildaddr()'s attempt to reconstruct an address.

buildaddr => output of printaddr() here (see Section 37.3.1)

Each recipient address for a mail message is added one-by-one to an internal list of recipients. The -d25.1 (a.k.a. -d25) debugging switch causes sendmail to print each address as it is added to this list:

sendto: list
   ctladdr= output of printaddr() here (see Section 37.3.1)

After each is added, those that have selected a delivery agent with the F=A (see Section 30.8.12, F=A) and F=w (see Section 30.8.43, F=w) flags set are further processed by aliasing and by reading the user's ~/.forward file. Each new address that results from this processing is added to the list, and any duplicates are discarded.

The -d26.1 (a.k.a. -d26) debugging switch causes sendmail to print the addresses of recipients as they are added to the send queue - an internal list of addresses that sendmail uses to sort and remove duplicates from the recipient addresses for a mail message.

On entry to the recipient() routine, the -d26.1 debugging switch causes sendmail to print the raw address (as it appears before adding it to the send queue):

recipient (level): output of printaddr() here (see Section 37.3.1)

An address can be the result of alias expansion. Because the process of aliasing (including :include: and .forward files) can be recursive, it is possible to get too many alias expansions. The level shows the number of alias expansions so far. If that number exceeds MaxAliasRecursion (as hard coded in conf.c as 10), sendmail issues this warning:

aliasing/forwarding loop broken (level aliases deep; MAXRCRSN max)

Next sendmail compares the new address to others that are already in the send queue. If it finds a duplicate, it prints the following message and skips the new address:

addr in sendq: output of printaddr() here (see Section 37.3.1)

Here, addr is the duplicate address. Information about that address is produced with the printaddr() routine.

Certain addresses can "self destruct" because they can cause an endless loop. Consider the address A. If A is aliased to B and B is aliased to A, A is a self-destructive address. The -d26.8 debugging switch causes sendmail to print the address that is being tested for self-destruction:

testselfdestruct: output of printaddr() here (see Section 37.3.1)

The -d26.10 debugging switch causes the entire send queue to be printed after the testselfdestruct above:

SENDQ:
output of printaddr() here (see Section 37.3.1)
--

The -d27.1 (a.k.a. -d27) debugging switch causes sendmail to print each step it takes when processing local addresses through aliasing. First, sendmail prints the addresses being aliased:

alias(addr)

Here, addr is the address (usually a local username) that is about to be aliased. Note that it may already be the result of previous aliasing. If the addr can be aliased, its transformation is printed as:

addr (host, user) aliased to newaddr

Here, addr is the address before aliasing, and the newaddr is the new address that resulted from successful aliasing. The host and user are the hostname and username from the recipient part of the envelope. If the addr cannot be aliased, nothing is printed.

During initialization, if the aliases database cannot be opened, the -d27.1 debugging switch causes sendmail to print:

Can't open aliasfile

Here, aliasfile is the full pathname of the aliases(5) file, as declared by the AliasFile (A) option (see Section 34.8.1, AliasFile (A)) or implied with the service-switch file and the ServiceSwitchFile option (see Section 34.8.61).

If the failure was due to a faulty map declaration, sendmail logs the following error:

setalias: unknown alias class mapclass

If the map is not one that is allowed to provide alias services, sendmail logs this error:

setalias: map class mapclass can't handle aliases

If sendmail is trying to create a database file and it can't (usually when it is run with the -bi command-line switch or run as newaliases), the -d27.1 debugging switch causes the following error to be printed:

Can't create database for filename: reason here

A self-destructive alias can cause a dangerous loop to occur. For example, the following two aliases can lead to a loop on the host mailhost:

jake:           Jake_Bair
Jake_Bair:      jake@mailhost

The -d27.1 debugging switch causes the following message to be printed when sendmail tests an address to see whether it loops:

self_reference(addr)
        ... no self ref                    if it didn't loop
        ... cannot break loop for "addr"   if it's unbreakable

An alias loop is unbreakable if no local username can be found in the list of aliases.

The -d27.1 debugging switch also causes sendmail to print the following message when it is attempting to read the user's ~/.forward file:

forward(user)

If the user has no home directory listed in the passwd(5) file, sendmail issues the following message with a syslog(3) level of LOG_CRIT:

forward: no home

The -d27.1 debugging switch also causes sendmail to print a warning if it cannot open or lock an alias file for automatic rebuilding (see Section 34.8.4, AutoRebuildAliases (D), the AutoRebuildAliases (D) option):

Can't open file:  reason here
newaliases: cannot open file:  reason here

Here, the error might be caused by the file simply not existing (as would be the case if it was NSF-mounted on a down host) or an I/O error (as would be the case for a bad disk).

warning: cannot lock file:  reason here

Failure to lock can be caused by system errors or by the file being read-only. Note that maintaining an aliases file under revision control can cause a read-only copy to exist, resulting in the following error:

Can't create database for file:  reason here
Cannot create database for alias file file

This error indicates that the output file (the dbm(3) or db(3) file) could not be created or written.

The -d27.2 debugging switch causes each :include: and .forward filename to be printed before each is opened for reading:

include(file)

The -d27.2 debugging switch also causes additional information to be printed for the alias loop check described above:

self_reference(addr)
        ... getpwnam(user)...found     if in passwd file
        ... getpwnam(user)...failed     otherwise

The -d27.2 debugging switch also causes sendmail to print a message every time it sleeps while waiting for the aliases database to be rebuilt:

aliaswait: sleeping for sec seconds

Also, when processing the ~/.forward file, sendmail may experience a temporary inability to read it (such as when an NFS server is down). In that case the -d27.2 debugging switch causes the following message to be printed:

forward: transient error on home

Here the message will be queued and tried again later.

The -d27.3 debugging switch causes each path for a possible .forward file to be printed before it is tried:

forward: trying file

Here, file is each file in the path of files declared by the ForwardPath (J) option (see Section 34.8.27, ForwardPath (J)).

The -d27.3 debugging switch also causes sendmail to trace its wait for another alias rebuild to complete (see Section 24.5.1, "Rebuild the Alias Database"). First sendmail prints the class (such as hash) and filename for which it will wait:

aliaswait(class:file)

If the database is not rebuildable (as would be the case with a network map class like nis, nis+, or hesiod), the -d27.3 debugging switch causes the following to be printed:

aliaswait: not rebuildable

If the file specified doesn't exist, the -d27.3 debugging switch prints

aliaswait: no source file

The -d27.3 debugging switch also causes sendmail to print an error message if there was a read error while processing a :include: or .forward file:

include: read error: reason here

A ~/.forward file must be owned by the user or by root. If it is not, it is considered unsafe, and sendmail ignores it. The -d27.4 debugging switch causes sendmail to print a message describing any such file it finds unsafe:

include: not safe (uid=uid)

Note that a file is considered unsafe if, among other things, it lacks all read permissions.

The -d27.4 debugging switch also causes sendmail to print information about a :include: file beyond that printed with -d27.2 above:

include(file)              printed with -d27.2
   ruid=ruid euid=euid     printed with -d27.4

This shows the real userID (ruid) and effective userID (euid) of the current running sendmail.

The -d27.4 debugging switch also causes sendmail to print an error if a :include: or ~/.forward file cannot be opened for reading:

include: open: reason here

The -d27.5 debugging switch tells sendmail to print several addresses with printaddr() (see Section 37.3.1) as each one is handled.

When an address is aliased to another, the original needs to be marked as one that shouldn't be delivered. The QDONTSEND below means just that:

alias: QDONTSEND output of printaddr() here (see Section 37.3.1)

If there was a self-reference, the retained address is printed like this:

sendtolist: QSELFREF output of printaddr() here (see Section 37.3.1)

If the original (before the test for a self-reference) is not the same as the retained address, the original must be marked for nondelivery:

sendtolist: QDONTSEND output of printaddr() here (see Section 37.3.1)

If an address resulted from a :include: or ~/.forward file, it will have a controlling user associated with it. That controlling user's address needs to be marked for nondelivery:

include: QDONTSEND output of printaddr() here (see Section 37.3.1)

The -d27.8 debugging switch tells sendmail to print the string passed to its internal setalias() routine.

setalias(what)

Here, what is one of the items listed with the AliasFile (A) option (see Section 34.8.1), such as /etc/aliases, or implied with the service-switch file and the ServiceSwitchFile option (see Section 34.8.61).

The -d27.9 debugging switch causes sendmail to trace the setting and resetting of its uid and gid identities when processing :include: and ~/.forward files. First an additional line is printed below the output of the -d27.2 and -d27.4 debugging switches:

include(file)              printed with -d27.2
   ruid=ruid euid=euid     printed with -d27.4
include: old uid = ruid/euid

The second and third lines above both contain the same information. After the new line is printed, sendmail may or may not change its identity depending on the nature of a :include: or ~/.forward file and that file's controlling user. Whether it changed or not, sendmail prints:

include: new uid = ruid/euid

After sendmail has finished processing a :include: or ~/.forward file, it resets its uid and gid back to their original values and displays the result:

include: reset uid = ruid/euid

The -d27.14 debugging switch causes sendmail to print the controlling user's address that led to the changing of the uid and gid or the currently running process:

include(file)                  printed with -d27.2
   ruid=ruid euid=euid         printed with -d27.4
ctladdr addr                   output of printaddr() produced with this -d27.14
include: old uid = ruid/euid   printed with -d27.9

The output of the printaddr() routine is described in Section 37.3.1.

The -d27.20 debugging switch causes sendmail to show how it is about to look up an alias in one of its database maps:

setalias(what)        printed with -d27.8
   map class:map what

Here, class is the type of map being looked up, such as hash or implicit (see Section 33.3, "The K Configuration Command"). The map is the map name, such as Alias0. The what is one of the items listed with the AliasFile (A) option (see Section 34.8.1), such as /etc/aliases, or implied with the service-switch file and the ServiceSwitchFile option (see Section 34.8.61).

The sendmail program can be compiled to use the user database (see Section 33.5, "The User Database") by defining USERDB in the Makefile (see Section 18.8.54, USERDB). If an address is selected by rule set 0 for delivery by a delivery agent with the F=l flag set, and if it remains unaliased even if the F=A flag is set, it is looked up in the user database. The -d28.1 (a.k.a. -d28) debugging switch is used to watch the interaction between sendmail and the user database:

udbexpand(addr)

Here, addr is the address being looked up.

The sender is looked up in a similar fashion. The intent in this case is to correct information such as the return address:

udbmatch(login, what)

Here, login is the login name of the sender and what is the mailname for sender lookups. If the lookup is via hesiod, sendmail will print the same information like this:

hes_udb_get(login, what)

If the sender is found in the database, sendmail prints:

udbmatch ==> login@defaulthost

Here, login may be a new login name. The defaulthost is either the sitewide host for all reply mail as defined in the user database or the default destination host for a particular user.

In the event that a db(3) style user database fails to open, the -d28.1 debugging switch displays the following error message:

dbopen(database):  reason for failure here

The -d28.2 debugging switch causes sendmail to print any failures in lookups:

udbmatch: no match on login (length) via method

This shows that the name login was looked up with a particular length, using the database method, where method is either db or hesiod.

The -d28.4 debugging switch causes sendmail to print the result of its attempt to open (initialize) each database. There are three possible results:

1. If a file on the local machine contains the information sought, sendmail prints

   FETCH: file fname

   Here, fname is the name of the local file.

2. If a mail message should be sent to another host for delivery, sendmail prints:

   FORWARD: host hostname

   Here, hostname is the full canonical name of the host that takes delivery.

3. An unknown result causes the address to remain unchanged and the following message to be printed:

   UNKNOWN

If sendmail is compiled with HES_GETMAILHOST defined (see Section 18.8.11, HES-GETMAILHOST), the following is printed when the -d28.8 debugging switch is used:

udbmatch: no match on login (length)   from -d28.2
  ... trying hes_getmailhost (login)
udbexpand: hesiod-getmail login stat err

Here, hes_getmailhost() is called to retrieve the name of the post office that handles this login. If that call fails, the last line is printed, showing that the hesiod error err occurred.

If a lookup is for a forwarding host (FORWARD above) and the forwarding host has MX records, the -d28.16 debugging switch causes those records to be printed:

getmxrr(host): number
    first MX record here
    second MX record here
    etc.

Here, host is the name of the host to which the lookup is forwarded. The number is the number of MX records found. That line is then followed by number MX records for that host.

The internal udb_map_lookup() routine is called each time anything is looked up in the udb database. Upon entry into that routine, the -d28.20 debugging switch causes sendmail to print

udb_map_lookup(name, what)

Here, the what is key about to be looked up in the map named name. This routine in turn calls udbmatch(). Note that the -d38.20 debugging switch also produces this output.

The -d28.80 debugging switch causes sendmail to show what it is about to lookup.

udbexpand: trying login (length) via method

This shows that the name login was looked up with a particular length, using the database method, where method is either db or hesiod.

The -d28.80 debugging switch also causes the result of a lookup to be displayed:

udbexpand: match login: result

Here, login was found, and the lookup returned result.

The -d28.80 debugging switch also causes the result of hes_udb_get() to be displayed:

hes_udb_get(login, what)             printed with -d28.1
hes_udb_get => result                printed with -d28.80

Here, the hesiod library routine hes_resolve(3) is called with the two arguments login and what. The result (a string) is printed on the second line.

With a level 2 or greater configuration file (see the V configuration command in Section 27.5, "The V Configuration Command"), V8 sendmail passes the user part ($u) of local recipient addresses through rule set 5 as a hook to select a new delivery agent. Rule set 5 is called if the address is unchanged after all aliasing (including the ~/.forward file). The -d29.1 (a.k.a. -d29) debugging switch causes the address to be printed as it appears before the rule set 5 rewrite:

maplocaluser: output of printaddr() here (see Section 37.3.1)

Information about the address is printed with the printaddr() routine. The output of maplocaluser() becomes the input to recipient(), so the result of rewriting can be seen by using the -d26.1 debugging switch in combination with this one.

Note that the particulars about whether or not an address will be processed by rule set 5 are described in -d29.5 below.

Fuzzy matching is the attempt to match a local recipient name to one of the names in the gecos field of the passwd(5) file (or NIS map). The -d29.4 debugging switch causes the process of fuzzy matching to be traced:

finduser(name)

Here, name is an address in the form of a local user address, without the host part. The name is first looked up in the passwd(5) file on the assumption that it is a login name. If it is found, sendmail prints

found (non-fuzzy)

If sendmail was compiled with hesiod support, all numeric login names will not work properly, resulting in the following:

failed (numeric input)

If the name is looked up and not found, the entire passwd(5) is searched, to see whether name appears in any of the gecos fields. This search is done only if MATCHGECOS (see Section 18.8.18, MATCHGECOS) was defined when sendmail was compiled and if the MatchGECOS (G) option (see Section 34.8.34, MatchGECOS (G)) is true. If MATCHGECOS was undefined, the search ends and the not-found name causes the mail to bounce. If the MatchGecos (G) option is false, sendmail bounces the message and prints the following:

not found (fuzzy disabled)

If the MatchGecos (G) option is true, the gecos fields are searched. But before the search starts, any underscore characters (and the character defined by the BlankSub (B) option; see Section 34.8.5, BlankSub (B)) that appear in name are converted to spaces. Then, in turn, each gecos field has the full name extracted (everything following the first comma, semicolon, or percent is truncated off, including that character), and any & characters found are converted to the login name. The two are then compared in a case-insensitive fashion. If they are identical, sendmail prints:

fuzzy matches gecos

If all gecos fields are compared and no match is found, sendmail bounces the message and prints the following:

no fuzzy match found

There is no debugging flag to watch each comparison.

The -d29.5 debugging switch causes sendmail to print an address just before it is tested to see whether rule set 5 should be called:

recipient: testing local?  cl=level, rr5=addr,
                                               
                                         output of printaddr() here (see Section 37.3.1)

For the address to be rewritten, the configuration file version as displayed by level must be 2 or more, the address in memory for rule set 5 (shown with rr5) must be nonzero, the flags in addr must not contain QNOTREMOTE, QDONTSEND, QQUEUEUP, or QVERIFIED, and the delivery agent for the address must have the F=5 flag set.

The -d29.5 debugging switch also causes sendmail to display the following if the address is rewritten by rule set 5:

maplocaluser: QDONTSEND output of printaddr() here (see Section 37.3.1)

Here the printaddr() routine prints the old address that is being canceled.

If a fuzzy match causes more than three transformations to occur during aliasing, sendmail emits the following error:

aliasing/forwarding loop for login broken

Here, login is the login name of the recipient that started the suspected runaway aliasing. The -d29.5 debugging switch also causes sendmail to print that it is trying to fall back to the original login name for delivery:

at trylocaluser login

Note that this message is printed before the message printed by the -d26 switch (which shows the testing for a self-destructive addresses).

When sendmail reads a mail message, it first collects (reads) the header portions of that message (everything up to the first blank line) and places the result into a temporary file in the queue directory. While it is processing the header, if the SaveFromLine (f) option (see Section 34.8.59, SaveFromLine (f)), is false, the UNIX-style "From " header is removed, and the important information in it is saved for later use.

The -d30.1 (a.k.a. -d30) debugging switch causes sendmail to print the following succinct message when it finds the end of the header portion of a mail message:

EOH

If end-of-headers was caused by a read error or a broken connection, sendmail prints:

collect: premature EOM:  reason for failure here

If end-of-headers was caused by a Message: or Text: header, then the rest of the header portion of the message is ignored.

The -d30.2 debugging switch first causes sendmail to print its entry into collect():

collect

Then, when sendmail strips (eats) the UNIX-style, five-character "From " header from a mail message, it tries to extract (and save) the date from the header. The -d30.2 debugging switch causes sendmail to print the field portion of the header as it appears before the date is extracted:

eatfrom(field)

The eatfrom() routine will vanish if NOTUNIX (see Section 18.8.32, NOTUNIX) is defined when compiling sendmail.

If the header of a mail message lacks recipient information (lacks all of the To:, Cc:, Bcc:, and Apparently-To: header lines), then sendmail adds a header as defined by the NoRecipientAction option (see Section 34.8.43, NoRecipientAction). The -d30.3 debugging switch causes sendmail to print which header it is adding:

Adding header: recipient

Here, header is the text of the header being saved, and recipient is the address of the recipient as taken from the envelope of the message.

The process of collecting the message header and body over an SMTP connection is driven by a state engine inside sendmail. The -d30.35 debugging switch causes sendmail to display each state just before it is processed:

top, istate=is, mstate=ms

Here, is is the current input state as described in Table 37.11 and ms is the current message state as described in Table 37.12.

Table 37.11: collect() Input States

istate	Name	Description
0	IS_NORM	Currently in middle of a line
1	IS_BOL	Currently at beginning of a line
2	IS_DOT	Just read a dot at beginning of line
3	IS_DOTCR	Just read ".\r" at beginning of line
4	IS_CR	Just read a carriage return

Table 37.12: collect() Message States

mstate	Name	Description
0	MS_UFROM	Currently reading UNIX from line
1	MS_HEADER	Currently reading message header
2	MS_BODY	Currently reading message body

The -d30.35 debugging switch also causes the same information to be printed every time sendmail goes to a new state:

nextstate, istate=is, mstate=ms, line = "header"

Here, the extra information is the current text of the header being processed.

The -d30.94 debugging switch causes sendmail to print the input state (see Table 37.11) for each character being processed:

istate=is, c=char (hex)

Each character is printed both as the character it is (char) and how it is represented in hexadecimal (hex).

Header lines (see Section 35.1, "The H Configuration Command") from the configuration file and from mail messages are processed by the chompheader() routine before they are included in any mail message. That routine parses each header line to save critical information, to check for validity, and to replace default values with new values.

The -d31.2 debugging switch [6] shows that sendmail is about to check whether it should replace a From: or Resent-From: header with the one defined by the H configuration command. If the configuration file is not being read and if sendmail is not processing the queue, the following test is made:

[6] There is no -d31.1 information.

comparing header from (header) against default (addr or name)

The value of the From: or Resent-From: header is compared to the sender's address (addr) and to the sender's name. If it is that same as either one, the address is replaced.

The -d31.6 debugging switch shows each header as it appears when it enters the chompheader() routine:

chompheader: line

Here, line is the exact text of the original header before processing. Unfortunately, there is no debugging switch that allows the result of this processing to be viewed.

To determine how it should handle a header, sendmail compares each header to its list of headers in sendmail.h. The -d31.6 debugging switch also shows the result after the comparisons have been done:

no header match

header match, hi_flags= flags in hexadecimal here

The flags and their hexadecimal equivalence are shown in Table 35.2 in Section 35.5, "Header Behavior in conf.c".

The -d32.1 (a.k.a. -d31) debugging switch causes sendmail to print the header lines that it collected from a received mail message:

--- collected header ---
     header lines here
--------------

Each header line is printed with the header name on the left, a colon, and the value for that header on the right. If there is no value, sendmail prints <NULL>.

If the H_DEFAULT flag is set for any header (see Section 35.5.3, "H_DEFAULT"), the value for the header is printed inside parentheses with macros unexpanded, just before it is printed in expanded form. For example,

Full-Name: ($x) Your Full Name

The -d32.2 debugging switch works only if the mode set with the -b command-line switch is in ARPA (-ba) mode (see Section 36.7.3, -ba). It shows the sender address being extracted from the header with setsender():

eatheader: setsender(*value == realvalue)

The setsender() routine can be further traced with the -d45.1 debugging switch.

The crackaddr() routine's job is to find an email address amidst other nonaddress text, then to save that nonaddress part:

[email protected] (George Washington)   crackaddr()  $g (George Washington)

The -d33.1 (a.k.a. 33) debugging switch causes sendmail to print the potential address prior to cracking and, after that, the address that it found:

crackaddr(potential)
crackaddr=>`addr'

The legal ways that addresses can be placed within other text is described in Section 35.3, "Header Field Contents". See also the /parse rule-testing command (Section 38.5.5, "Parse an Address with /parse") to put crackaddr() in context.

The sendmail program uses putheader() to create headers that didn't exist before. The -d34.1 (a.k.a. -d34) debugging switch causes sendmail to print the following on entry to that routine:

-- putheader, mailer = agent --

Here, agent is the symbolic name of the delivery agent that will deliver the bounced message.

Each header line created is displayed with two leading spaces. For example,

-- putheader, mailer = *file* --
  Return-Path: you

Then certain headers are excluded from the bounced mail message header. Those with the H_CTE flag set (see Section 35.5.12, "H_CTE") and either the MCIF_CVT8TO7 or MCIF_INMIME mci flags set (see Table 37.17) will have the text:

(skipped (content-transfer-encoding))

appended and that header skipped (excluded).

Any header that has both H_CHECK and H_ACHECK flags set and doesn't have identical delivery agent flags set for itself and its cached connection information will also be skipped:

(skipped)

All resent headers (those marked with H_RESENT) are also skipped:

(skipped (resent))

Return-receipt headers are also skipped:

(skipped (receipt))

If a Bcc: header (see Section 35.10.4, Bcc:) is being skipped, this is printed:

(skipped - bcc)

Finally, valueless headers are also skipped with this message:

(skipped - null value)

Any headers that survive this skipping process are included in the eventually delivered bounced message. Note that MIME headers are not generated or displayed here (see -d43).

The -d35.9 debugging switch [7] causes sendmail to print each macro as it is defined. The output looks like this:

[7] There is no -d35.1 information.

define(name as "value")

Here, the name is the macro's name, and the value is the value (text) assigned to the macro. If the macro already has a value assigned to it, sendmail prints:

redefine(name as "value")

With the introduction of multicharacter macro names, it is now necessary for sendmail to convert each macro name from text form into sendmail's internal form. Single-character macro names are represented by themselves. Multicharacter names are represented by values from 0240 (octal) upward. The -d35.14 debugging switch causes sendmail to print each macro name as it is being looked up:

macid(name) => value

The name is the text immediately following a $ character, including any trailing junk in the line. For example, the following miniconfigurations file:

V7
D{FOO}foo
R$H     ${FOO}  note no $H defined

produces this output (with only the macid lines shown):

macid({FOO}foo) => 0xa0
macid(H\t${FOO}\tnote no $H defined) => H
macid({FOO}\tnote no $H defined) => 0xa0
macid(H defined) => H

Macros that are included in text must be translated into values (expanded) so that the values may be used. The -d35.24 debugging switch tells sendmail to display such text both before and after the macros in it have been expanded. The "before" looks like this:

expand("text")

For example,

expand("$w.$D")

The text (here $w.$D) may be any ASCII string. In it, special characters like the newline character are printed in C language, backslash-escaped notation (such as \n). Macros are printed with either the $ prefix (such as $w above with V8 sendmail) or some other prefix (IDA uses ^Aw.^AD, SunOS uses /w./D; others use the archaic \001w.\001D notation).

Expansion is performed only on defined macros (using the $ prefix), on macro conditionals (in which one of two values is used, depending on whether a macro has a value or not, such as $?x$x$|nobody$.), and and on the $& prefix (deferred expansion).

After the first (leftmost) macro or conditional is expanded in text, sendmail prints the transformed text as follows:

expanded ==> "text"

For example,

expanded ==> "wash.$D"

If any unexpanded macros or conditionals remain in text, this expanded process is recursively repeated until everything that can be expanded has been expanded. This process of recursion allows macros to have other macros as their values.

The symbol table is a block of memory that contains information about all the symbolic names used by sendmail. Symbolic names are delivery agent names (such as local), aliases, database classes, hostnames, and macros. Symbols are placed into the symbol table with the stab() routine. That routine is also used to see whether a symbol has already been inserted and, if so, to obtain its value. The -d36.5 debugging switch [8] causes sendmail to print the following upon its entry into the stab() routine:

[8] There is no -d36.1 information.

STAB: name type

Here, name is the symbolic name to be inserted or looked up. The type is one of the values listed in Table 37.13.

Table 37.13: Types of Symbols Recognized by stab()

Type	Mnemonic	Description
0	ST_UNDEF	Undefined type
1	ST_CLASS	Class (from C and F configuration commands)
2	ST_ADDRESS	An address in parsed format
3	ST_MAILER	A delivery agent (from M configuration command)
4	ST_ALIAS	An alias, if no external database
5	ST_MAPCLASS	A database class (K command)
6	ST_MAP	Function that handles a class
7	ST_HOSTSIG	Host MX signature
8	ST_NAMECANON	Cached canonical name
9	ST_MACRO	Macro name to id value mapping
10	ST_RULESET	Ruleset name to number mapping
11	ST_SERVICE	Service switch file entry
16	ST_MCI	SMTP connection status\*[=a]

This is the base (offset) of types 16 through 16+n, where n is 16 plus MAXMAILERS as defined in conf.h. If stab() is being used to insert a symbol, the above output is concluded with:

entered

If stab() is being used to look up a symbol, one of the two following messages is printed:

not found
type type val hex hex hex hex

If it is found, four hexadecimal values are printed, which show the first four 4-byte words of the value.

A hashing algorithm is used to make the symbol table more efficient. The -d36.9 debugging switch is used to see the hash value selected for any given symbol:

(hfunc=hash)

The number of possible hash-table buckets is limited by STABSIZE, as defined in stab.c. [9]

[9] You can experiment with different hashing algorithms by modifying the code in stab.c. But note that it has already been heavily tuned in V8.7, roughly doubling its speed over that of earlier versions.

The -d36.90 debugging switch causes the name and type of each symbol to be printed as a common function is applied to each with sendmail's internal stabapply() function.

stabapply: trying type/name

The stabapply() routine is used to initialize maps and to print the members of a class.

Options can be set on the command line or in the configuration file. The -d37.1 (a.k.a. -d37) debugging switch allows you to watch each option being defined. As each is processed, this message is first printed, without a trailing newline:

setoption: name (char).sub=val

Here, name is the option's multicharacter name, char is its single-character equivalent (or a hexadecimal value if it is non-ASCII), and sub is the subvalue for that option if there was one. Finally, val is the value being given to that option. If the option has already been set from the command line and is thus prohibited from being set in the configuration file, sendmail prints:

(ignored)

A newline is then printed, and the job is done. If defining the option is permitted, sendmail next checks to see whether it is safe. If it is not, sendmail prints:

(unsafe)

If it is unsafe, sendmail checks to see whether it should relinquish its root privilege. If so, it prints:

(Resetting uid)

A newline is then printed, and the option has been defined. Options in general and safe versus unsafe are covered in Chapter 34, Options.

The adding of words to a class (C or F configuration commands) can be traced with the -d37.8 debugging switch. Each word is printed like this:

setclass(name, text)

The text is added to the class whose symbolic name is name. Class names can be single-character or multicharacter (see Section 32.1, "Class Configuration Commands").

Most maps are declared directly with the K configuration command (see Section 33.3). Others are declared internally by sendmail, such as the host and alias maps. The -d38.2 debugging switch [10] first shows maps being initialized:

[10] There is no -d38.1 information.

map_init(class:name, file, pass)

Here, class is one of the internal classes allowed by sendmail, such as host, and dequote (see Section 33.3, the K configuration command). The name is either the name you gave to the map with the K configuration command or one assigned internally by sendmail (like aliases.files). The file is either NULL or the name of the database file (such as /etc/aliases). And pass is a flag that tells sendmail whether or not it should open the database, rebuild the database, or do neither.

Next the -d38.2 debugging switch causes sendmail to show each map as it is about to be opened. The output that is produced will look like one of the following lines:

bt_map_open(name, file, mode)
hash_map_open(name, file, mode)
hes_map_open(name, file, mode)
impl_map_open(name, file, mode)
ldap_map_open(name, mode)
ndbm_map_open(name, file, mode)
ni_map_open(name, file, mode)
nis_map_open(name, file, mode)
nisplus_map_open(name, file, mode)
stab_map_open(name, file, mode)
switch_map_open(name, file, mode)
text_map_open(name, file, mode)
user_map_open(name, mode)

In all of the previous lines, the mode is a decimal representation of the file permissions that are used during the open. The name prefixing each line corresponds to the class of map. For example, impl corresponds to the implicit class.

The -d38.2 debugging switch also causes sendmail to display the nis domain that was used if one was specified for the nisplus class:

nisplus_map_open(file): using domain ypdomain

The -d38.2 debugging switch also allows other silent errors to be printed about some open failures. Under nis+, lookups are performed by named columns (as in the case of the password database, the columns are named passwd, shell, and so on):

nisplus_map_open(name): can not find key column colname
nisplus_map_open(name): can not find column colname

Text files that are used as maps must be declared with a filename that is an absolute path (begins with a / character thus forming a fully qualified pathname), that exists, and that is a regular file. If there is a problem, one of the following is logged (even if -d38.2 is not specified):

text_map_open: file name required
text_map_open(file): file name must be fully qualified
text_map_open(name): can not stat file
text_map_open(name): file is not a file

Text files should be syntactically correct. The delimiting character, char, will print either as a single character or as the phrase (whitespace). Note that the third line below will be reported only when the -d38.2 debugging switch is used:

text_map_open(file): -k should specify a number, not badtext
text_map_open(file): -v should specify a number, not badtext
text_map_open(file): delimiter = char

The sendmail program initializes maps in passes so that it can open a map for reading or rebuild. That is, pass 0 opens it for reading only, and passes 1 and 2 open it for updating. This gives sendmail the opportunity to detect optional maps. The -d38.3 debugging switch causes sendmail to print wrong pass every time it skips rebuilding because the pass is inappropriate:

map_init(class:name, file, pass)   from -d38.2
wrong pass

The -d38.3 debugging switch also causes sendmail to print a failure message if an implicit class map does not exist:

impl_map_open(name, file, mode)    from -d38.2
no map file

When rebuilding the aliases files, each database is opened before it is rebuilt or not. The -d38.4 debugging switch shows the success or failure of each open:

map_init(class:name, file, pass)   from -d38.2
     class:name file valid or invalid

The status is valid if the open succeeded; otherwise, it is invalid.

The -d38.4 debugging switch also shows each map being looked up in a switch class map (see Section 33.8.17, switch).

switch_map_open(name, file, mode)   from -d38.2
        map_stack[index] = class:name

If the name is not one that was declared in a K configuration command, the following error is printed:

Switch map class: unknown member map name

The -d38.9 debugging switch traces map closures for those kind of maps that can be closed:

ndbm_map_close(name, file, flags)
db_map_close(name, file, flags)
impl_map_close(name, file, flags)
prog_map_lookup(name) failed (errno) - closing
seq_map_close(name)

Here, the name is either the name you gave to the map with the K configuration command or one assigned internally by sendmail (like aliases.files). The file is the filename on disk that contains the database. The flags describe the specific features of a map. They are printed in hexadecimal, and the meanings of the values printed are listed in Table 37.14.

Table 37.14: Flags Describing Properties of Database Maps

Hex	Text	Description
00001	MF_VALID	This entry is valid.
00002	MF_INCLNULL	Include null byte in key.
00004	MF_OPTIONAL	Don't complain if map not found.
00008	MF_NOFOLDCASE	Don't fold case in keys.
00010	MF_MATCHONLY	Don't use the map value.
00020	MF_OPEN	This entry is open.
00040	MF_WRITABLE	Open for writing.
00080	MF_ALIAS	This is an alias file.
00100	MF_TRY0NULL	Try with no null byte.
00200	MF_TRY1NULL	Try with the null byte.
00400	MF_LOCKED	This map is currently locked.
00800	MF_ALIASWAIT	Alias map in aliaswait state.
01000	MF_IMPL_HASH	Implicit: underlying hash database.
02000	MF_IMPL_NDBM	Implicit: underlying ndbm database.
04000	MF_UNSAFEDB	This map is world writable.
08000	MF_APPEND	Append new entry on rebuild.
10000	MF_KEEPQUOTES	Don't dequote key before lookup.

In addition to tracing map closures, the -d38.9 debugging switch traces map appends allowed by the MF_APPEND flag (see Section 33.3.4.1, "-A append values for duplicate keys (V8.7 and above)") as specified when the database is declared by the K configuration command:

ndbm_map_store append=new
db_map_store append=new

Here new is new value appended to the old. Since this property is used for alias files, the new and old values have a comma inserted between them.

The NIS alias map needs to contain a @:@ entry to indicate that it is fully updated and ready for reading. But because HP-UX omits the @:@, it is useful only as a check to see whether the NIS map exists. The -d38.10 debugging switch causes the result of this check to be printed as:

nis_map_open: yp_match(@, domain, nismap)

Here, domain is the NIS domain, and nismap is usually mail.aliases (but it can be redefined in your configuration file; see Section 34.8.1). If the map is not marked as optional (see Section 33.3.4.8, "-o the database file is optional (V8.1 and above)"), the following error will be printed:

Cannot bind to map nismap in domain domain:  reason here

The -d38.10 debugging switch also traces the NIS+ open's check for a valid table.

nisplus_map_open: nisplusmap.domain is not a table

Essentially, this says that the NIS+ map nisplusmap (in the domain shown) does not exist. The error is printed even if the -o (optional) database switch (see Section 33.3.4.8) is missing.

The -d38.12 debugging switch shows values being stored in maps that support updates.

db_map_store(name, key, value)
ndbm_map_store(name, key, value)
seq_map_store(name, key, value)

Here, the name is either the name you gave to the map with the K configuration command or the name assigned internally by sendmail (like aliases.files). The key is the key for which the new value is being stored, and the value is the value for that key.

A switched map is one that, either as the result of a service-switch file or because of sendmail's internal logic, causes lookups to follow a select path. For example, Sun's Solaris 2 nsswitch.conf might specify that aliases be looked up in the order files, then nis:

switch_map_open(name, file, mode)   from -d38.2
switch_map_find => nmaps
                maptype
                ...

First the number of maps found is printed with nmaps, then each type of map found in the list is printed. Each is a class name, such as files, or nis.

The -d38.20 debugging switch traces many different map lookups. The getcanonname() routine looks up a hostname and tries to canonify it:

getcanonname(host), trying maptype
getcanonname(host), found
getcanonname(host), failed, stat=error

Here, host is the hostname that is being looked up, and maptype is one of files, nis, nisplus, dns, or netinfo. If the canonical name is not found, the error shows one of the errors listed in <sysexits.h>. The process of canonifying the name is handled by calling special subroutines based on the maptype:

text_getcanonname(host)				 maptype is files
nis_getcanonname(host)				 maptype is nis
nisplus_getcanoname(host), qbuf=query		 maptype is nisplus
dns_getcanonname(host, flag)			 maptype is dns, printed with -d8.2
ni_getcanonname(host)				 maptype is netinfo

The nisplus_getcanoname() routine is far more verbose than the other. In addition to the information printed above, the -d38.20 switch also prints

nisplus_getcanoname(host), got count entries, all but first ignored
nisplus_getcanoname(host), found in directory "nisdir"
nisplus_getcanonname(host), found result
nisplus_getcanonname(host), failed, status=nsistatus, nsw_stat=errno

The -d38.20 debugging switch also traces general lookups in various kinds of databases. Again note that nisplus is more verbose than the others:

ndbm_map_lookup(name, key)
db_map_lookup(name, key)
nis_map_lookup(name, key)
nisplus_map_lookup(name, key)
qbuf=query
nisplus_map_lookup(key), got count entries, additional entries ignored
nisplus_map_lookup(key), found value
nisplus_map_lookup(key), failed
hes_map_lookup(name, key)
ni_map_lookup(name, key)
stab_lookup(name, key)
impl_map_lookup(name, key)
user_map_lookup(name, key)
prog_map_lookup(name, key)
prog_map_lookup(name): empty answer
seq_map_lookup(name, key)

Here, the name is either the name you gave to the map with the K configuration command or one assigned internally by sendmail (such as aliases.files). The key is the item being looked up. The file is the pathname of the file that contains the database.

The -d38.20 debugging switch described above prints the nis lookup of the canonical hostname. This -d38.44 debugging switch prints the result of that lookup:

nis_getcanonname(host)           from -d38.20
got record `result\'

When the RHS of a rule matches an entry in a database map with $( and $), that entry replaces the key. If the entry contains %digit literals, they are replaced by corresponding $@ values in the RHS (see Section 33.4.2, "Specify Numbered Substitution with $@").

The -d39.1 (a.k.a. -d39) debugging switch causes sendmail to print the entry and any replacement values:

map_rewrite(entry), av =
       value1
       value2
       ...etc

After the RHS is rewritten (after all the $@ values have replaced all the %digit literals), sendmail prints the result:

map_rewrite => rewritten RHS here

The -d40.1 (a.k.a. -d40) debugging switch traces the placing of a mail message into the queue and the processing of queued files.

When a mail message is placed into the queue, its qf file is written as a tf temporary file; then that temporary file is closed and renamed to be the qf file. The -d40.1 debugging switch causes sendmail to announce that it is beginning that process by printing the queued message's identifier:

>>>>> queueing qid(new id) >>>>> 
queueing  for each recipient, output of printaddr() here (see Section 37.3.1)
<<<<< done queueing qid <<<<<

First, the queue identifier is printed (qid). If this identifier is brand-new, the phrase "(new id)" is printed. Next, sendmail prints complete information about each recipient for the message using the printaddr() routine. Finally, done queueing is printed, and the queuing of the qid item is finished.

When sendmail processes files in the queue, it first prereads all the qf files and sorts the jobs by priority. After the list has been sorted, the -d40.1 debugging switch causes sendmail to print that list, one message per line, in the following format:

qfname: pri=priority

Here, qfname is the basename of the qf file, and priority is the current priority of each message (see Section 34.8.53, RecipientFactor (y)). After the sorted list of messages has been processed, and if there are any messages in that list, sendmail attempts to deliver each of the messages in the order in which it appears in the list. The -d40.1 debugging switch causes sendmail to print the following line of information for each message processed:

dowork: (qfname)

The -d40.3 debugging switch causes the envelope flags for each message to be printed as it is queued:

>>>>> queueing qid(new id) >>>>>  from -d40.1
  e_flags=  output of printenvflags() here

The envelope flags are described in Table 37.3 in Section 37.5.12.

The qf file is composed of individual lines of information (see Section 23.9.11, P line). The -d40.4 debugging switch causes sendmail to print each of those lines as it is read:

+++++ Xtext

Each line begins with five plus characters. The qf file's key letter (here, X) follows, then the rest of the text that made up that line. In the qf file, indented lines (lines that begin with a space or tab character) that immediately follow the key line are appended to that key line. Those joined lines are printed after they are joined. Note that the lines of the qf file are printed before they are processed by sendmail. An error in a line is printed after the line is printed.

If the queue file could not be read, the -d40.4 debugging switch instead causes sendmail to print this error:

readqf(qid) failed

Here, qid is the queue identifier for the message. Note that reading can legitimately fail if the queue file is locked. Use -d40.8 (described below) to see the exact reason for failure.

The -d40.8 debugging switch causes sendmail to print the reason it could not process a message's qf file. One possibility is:

readqf(qfname): fopen failure (error text here)

If the failure was caused by anything other than the file's nonexistence, the following is also logged:

readqf: no control file qfname

If the qf file could not be read because it is locked by another incantation of sendmail (a valid reason), the -d40.8 debugging switch prints:

qid: locked

Here, qid is the identifier portion of the qf file. If the log level is set to greater than 19 (see the LogLevel (L) option, Section 34.8.33, LogLevel (L)), the above message will also be logged.

For security the sendmail program fstat(2)'s the qf file after it is open to make sure it cannot be fooled by a race condition. If that fstat(2) fails, the following is printed if the -d40.8 debugging switch was specified:

readqf(qid): fstat failure (error text here)

If the qf file is owned by someone other than the effective uid of sendmail, the qf file will be renamed into a Qf file (see Section 23.3, "A Bogus qf File (V8 only): Qf"). If this -d40.8 debugging switch was specified, the following message will also be printed:

readqf(qid): bogus file

The MinQueueAge option (see Section 34.8.41, MinQueueAge) determines the interval between queue runs for any given file. If a qf file was not last run at least MinQueueAge minutes ago, it is skipped and the -d40.8 debugging switch causes the following message to be printed:

qid: too young (howlong)

If the log level is set to greater than 19 (see the LogLevel (L) option, Section 34.8.33), the above message will also be logged.

After sendmail has opened the qf file (with -d40.1) and printed the envelope flags (with -d40.3), this -d40.9 debugging switch will cause the file descriptors for the qf file and its corresponding lock file to be dumped:

>>>>> queueing qid(new id) >>>>>  from -d40.1
 e_flags=                        from -d40.3
 tfp=  output of dumpfd() here
 lockfp=  output of dumpfd() here

The e_flags are described in Table 37.3 of Section 37.5.12. Here, tfp= shows the file descriptors for the qf file, and lockfp= shows the descriptors for the lock. See -d2.9 (Section 37.5.13) for a description of output of dumpfd().

The -d40.32 debugging switch causes sendmail to dump the list of message recipients:

>>>>> queueing qid(new id) >>>>>  from -d40.1
  e_flags=                        from -d40.3
  sendq=  output of printaddr()) here (see Section 37.3.1)
  tfp=                            from -d40.9
  lockfp=                         from -d40.9

The -d41 (a.k.a. -d41) debugging switch causes sendmail to print its ordering of the queue. First it prints

orderq:
        QueueLimitId = qid             if -qI used
        QueueLimitSender = sid         if -qS used
        QueueLimitRecipient = rid      if -qR used

See Section 23.6.2.3, "Process by identifier/recipient/sender: -q[ISR]" for an explanation of how the -qI, -qS, and -qR command-line switches can limit the scope of a queue run. If none of them were specified, only orderq: is printed. The -d41.1 debugging switch is extremely handy for previewing the effect of the -qI, -qS, and -qR command-line switches. When combined with -bp (mailq), these switches limit the queue listing and thus preview the effect of a limited queue run:

% mailq
                Mail Queue (1 request)
-Q-ID- -Size- ---Q-Time--- ------Sender/Recipient------
MAA11111     4560 Tue Dec 31 12:37 you
                                   [email protected]
% mailq -d41.1 -qI22222
orderq:
        QueueLimitId = 22222
Mail queue is empty

The -d41.1 debugging switch also traces the growth of the queue working list. Every time the limit of that list is reached, the internal routine grow_wlist() is called to extend the list size by QUEUESEGSIZE (where QUEUESEGSIZE is described in Section 18.8.38, QUEUESEGSIZE).

grow_wlist: WorkListSize=current
grow_wlist: WorkListSize now newsize

If the log level is set to greater than 1 (see the LogLevel (L) option, Section 34.8.33), the following is also logged each time the list size grows:

grew WorkList for qdirectory to newsize

If the size could not be increased (because the program reached the limit of available memory) and if the LogLevel (L) option is greater than 0, sendmail will log this error at LOG_ALERT:

FAILED to grow WorkList for qdirectory to newsize

This message will repeat until there are no more queue entries to process after the limit is received. However, all the files that are already in the work list will be processed, so presumably the next run will catch the failed messages.

Ordinarily, sendmail is silent about failures to open a qf file, but the -d41.2 debugging switch causes it to print the reason the open failed:

orderq: cannot open qfname (reason for failure here)

Here, qfname is the name of the qf file that could not be opened.

The 41.49 debugging switch causes sendmail to display the queue files that were not included in the work list:

skipping qfname (bit)

Here, the bit is a hexadecimal representation of the requirement that was not met. These bits are listed in Table 37.15.

Table 37.15: Bits Describing a Queue Run's Requirements

Hex	Mnemonic	Description
1	NEED_P	Priority must be high enough (required qf file line)
2	NEED_T	Must have been in queue long enough (required qf file line)
4	NEED_R	Match a recipient
10	NEED_S	Match a sender

Note that nothing will be printed if the message was skipped because its identifier did not match the -qI specification.

The sendmail program scans the queue directory looking for all the qf files to set up its working list. If a file doesn't start with the letters "qf," it is ordinarily silently skipped. The -d41.50 debugging switch causes sendmail to display every single file it finds in its queue directory:

orderq: checking file

The file can be a directory, such as .., or a regular file, such as a df or qf file.

V8 sendmail can be configured with the ConnectionCacheSize (k) option (see Section 34.8.10, ConnectionCacheSize (k)) to maintain open SMTP connections to a few other hosts. Before making a new SMTP connection, sendmail checks to see if it already has one established. The -d42.2 [11] debugging switch causes sendmail to print the result of that check.

[11] Note that there is no -d42.1 information.

mci_get(host mailer): mci_state=state, _flags=flag, _exitstat= stat, _errno=err

Here, the host is the name of the host to which the connection is to be made, and the mailer is the symbolic name of the delivery agent. The state is the status of the current SMTP connection (if there is one) as shown in Table 37.16.

Table 37.16: mci_get() Connection States

State	Mnemonic	Description
0	MCIS_CLOSED	No traffic on this connection
1	MCIS_OPENING	Sending initial protocol
2	MCIS_OPEN	Connection is open
3	MCIS_ACTIVE	Message being sent
4	MCIS_QUITING	Running SMTP quit protocol
5	MCIS_SSD	SMTP service shutting down
6	MCIS_ERROR	I/O error on connection

The flag describes the overall status of the connection. It can have one or more values from those shown in Table 37.17 where those values are OR'd together.

Table 37.17: mci_get() Status Flags

Flag	Mnemonic	Description
0x0001	MCIF_VALID	If set, this entry is valid
0x0002	MCIF_TEMP	If set, don't cache this connection
0x0004	MCIF_CACHED	If set, connection is currently in open cache
0x0008	MCIF_ESMTP	This host speaks ESMTP
0x0010	MCIF_EXPN	EXPN command supported
0x0020	MCIF_SIZE	SIZE option supported
0x0040	MCIF_8BITMIME	BODY=8BITMIME supported
0x0080	MCIF_7BIT	Strip this message to 7 bits
0x0100	MCIF_MULTSTAT	MAIL11V3, handles MULT status
0x0200	MCIF_INHEADER	Currently outputting header
0x0400	MCIF_CVT8TO7	Convert from 8 to 7 bits
0x0800	MCIF_DSN	DSN extension supported
0x1000	MCIF_8BITOK	Okay to send 8 bit characters
0x2000	MCIF_CVT7TO8	Convert from 7 to 8 bits
0x4000	MCIF_INMIME	Currently reading MIME header

The stat is the exit status of the last delivered mail message to this connection. It is one of the values defined in <sysexits.h>. The err is the value of the last system error (if any), as defined in <errno.h>.