an electronic mail transport agent

sendmail [flags] [address]
mailq [-v]

Sendmail sends a message to one or more recipients

Sendmail is not intended as a user interface routine; other programs provide user-friendly front ends; sendmail is used only to deliver preformatted messages.

With no flags, sendmail reads its standard input up to an end-of-file or a line consisting only of a single dot and sends a copy of the message found there to all of the addresses listed.
It determines the network(s) to use based on the syntax and contents of the addresses.

Local addresses are looked up in a file and aliased appropriately.
Aliasing can be prevented by preceding the address with a backslash.
the sender is included in any alias expansions, e.g., if `john' sends to `group', and `group' includes `john' in the expansion, then the letter will also be delivered to `john'.

-bh output the persistent host status database.
-bm Deliver mail in the usual way (default).
-bp list the queue(s).
-Queue ID-  --Size-- ----Arrival Time---- -Sender/Recipient-------
C52D01EB396*     334 Thu Sep  7 19:26:19  uname@locahostname.localdomain

0EC6A1EB429*     334 Thu Sep  7 19:27:03  uname@locahostname.localdomain
-- .6 Kbytes in 2 Requests.
-bs Use the SMTP protocol on standard input and output. implies all the operations of -ba compatible with SMTP.
-bt Run in address test mode, reads addresses and shows the steps in parsing; for debugging configuration tables.
-bv verify names of users and mailing lists only.
-- end of flags, use the rest of the arguments as addresses.
-C file alternate configuration file. gives up any enhanced set-user-ID or set-group-ID privileges
-D logfile Send debugging output to logfile instead of stdout.
-d category.level... Set the debugging flag
category is an integer or a name specifying the topic.
level an integer higher levels generally mean more output.
More than one flag can be specified by separating them with commas.
List of numeric debugging categories can be found in TRACEFLAGS
-d0.1 prints the version of sendmail and the options it was compiled with.
-Ffullname of the sender.
-fsender the from person (seems to be same as -r)
-rsender envelope sender address. This is the address where delivery problems are sent .
This address may also be used in the From: header if that header is missing during initial submission. The envelope sender address is used as the recipient for delivery status notifications and may also appear in a Return-Path: header.
-f should only be used by ``trusted'' users (normally root, daemon, and network) or
if the person you are trying to become is the same as the person you are. Otherwise, an X-Authentication- Warning header will be added to the message.
-G gateway) submission of a message, e.g., when rmail calls sendmail .
-h n Set the hop count, incremented every time the mail is processed.
When it reaches a limit, the mail is returned with an error message, the victim of an aliasing loop.
If not specified, ``Received:'' lines in the message are counted.
-i ignore dots alone on lines by themselves in incoming messages, reading data from a file.
-L tag identifier used in syslog messages to tag.
-N dsn delivery status notification conditions to dsn, which can be `never' for no notifications or
a comma separated list of the values `failure' `delay' and `success'
-n no aliasing.
-O option=value long names. See below for more details.
-ox value Set option x Sendmail Installation and Operation Guide
-pprotocol to receive the message. ``UUCP'' or a protocol and hostname, such as ``UUCP:ucbvax''.
-q[time] Process saved messages in the queue at given intervals.
If time is omitted, process the queue once.
Time is given as a tagged number, with `s' being seconds, `m' being minutes (default), `h' being hours, `d' being days, and `w' being weeks.
For example, `-q1h30m' or `-q90m' would both set the timeout to one hour thirty minutes. By default, sendmail will run in the background. used safely with -bd. (daemon mode)
-qp[time] Similar to -qi, except that instead of periodically forking a child , sendmail forks a single persistent child for each queue that alternates between processing the queue and sleeping.
The sleep time is given as the argument; and defaults to 1 second.
The process will always sleep at least 5 seconds if the queue was empty in the previous queue run.
-qf Process saved messages in the queue once and do not fork(), but run in the foreground.
-qGname Process jobs in queue group called name only.
-q[!]I substr Limit processed jobs to those Including var> substr as a substring of the queue id or not when ! is specified.
-q[!]Qsubstr Limit processed jobs to qcuarantined jobs containing substr as a substring of the quarantine reason or not when ! is specified.
-q[!]Rsubstr Limit processed jobs to those containing substr as a substring of one of the recipients or not when ! is specified.
-q[!]Ssubstr Limit processed jobs to those containing substr as a substring of the sender or not when ! is specified.
-Q[reason] Quarantine a normal queue items with the given reason or unquarantine quarantined queue items if no reason is given.
This should only be used with some sort of item matching using as described above.
-R full|hdrs Set the amount of the message to be returned if the message bounces.
-t Read message for recipients. To:, Cc:, and Bcc: lines will be scanned for recipient addresses. The Bcc: line will be deleted before transmission.
-V envid Set the original envelope id. propagated across SMTP to servers that support DSNs and is returned in DSN-compliant error messages.
-v verbose . Alias expansions will be announced, etc.
-X logfile Log all traffic in and out of mailers in the indicated log file.
This should only be used as a last resort for debugging mailer bugs. It will log a lot of data very quickly.
-Ac Use even if the operation mode does not indicate an initial mail submission.
-Am Use even if the operation mode indicates an initial mail submission.
-B 7BIT | 8BITMIME Set the body type
-bH Purge expired entries from the persistent host status database.
-bi Initialize the alias database.
-ba ARPANET mode. input lines must end with a CR-LF, and all messages will be generated with a CR-LF at the end. From: and Sender: fields are examined for the name of the sender.
-bd Run as a daemon. socket 25 for incoming SMTP connections. normally run from /etc/rc.
-bD Same as -bd except runs in foreground.
-bP Print number of entries in the queue(s); only available with shared memory support.
processing options on the command line using -o (for short names), -O (for long names), or in the configuration file.
partial list limited to those options that are likely to be useful on the command line and only shows the long names; for a complete list consult the Sendmail Installation and Operation Guide. Normally these will only be used by a system administrator.
AliasFile=file Use alternate alias file.
HoldExpensive On mailers that are considered ``expensive'' to connect to, don't initiate immediate connection. This requires queueing.
CheckpointInterval=n Checkpoint the queue file after every n successful deliveries (default 10). This avoids excessive duplicate deliveries when sending to long mailing lists interrupted by system crashes.
DeliveryMode=x Set the delivery mode to x.
`i' for interactive (synchronous) delivery,
`b' for background (asynchronous) delivery,
`q' for queue only - i.e., actual delivery is done the next time the queue is run, and
`d' for deferred - the same as `q' except that database lookups for maps which have set the -D option (default for the host map) are avoided.
ErrorMode= Set error processing to mode x.
`m' to mail back the error message,
`w' to ``write'' back the error message (or mail it back if the sender is not logged in),
`p' to print the errors on the terminal (default),
`q' to throw away error messages (only exit status is returned), and
`e' to do special processing for the BerkNet.

If the text of the message is not mailed back by modes `m' or `w' and if the sender is local to this machine, a copy of the message is appended to the file dead.letter in the sender's home directory.

SaveFromLine Save UNIX-style From lines at the front of messages.
MaxHopCount=c maximum number of times a message is allowed to ``hop'' before it is considered a loop.
IgnoreDots Do not take dots on a line by themselves as a message terminator.
SendMimeErrors Send error messages in MIME format. If not set, the DSN (Delivery Status Notification) SMTP extension is disabled.
ConnectionCacheTimeout=seconds Set connection cache timeout.
ConnectionCacheSize=N Set connection cache size.
LogLevel=n The log level.
MeToo=False Don't send to ``me'' (the sender) if I am in an alias expansion.
CheckAliases Validate the right hand side of aliases during a newaliases(1) command.
OldStyleHeaders If set, this message may have old style headers. If not set, this message is guaranteed to have new style headers (i.e., commas instead of spaces between addresses). If set, an adaptive algorithm is used that will correctly determine the header format in most cases.
QueueDirectory=queuedir Select the directory in which to queue messages.
StatusFile=file Save statistics in the named file.
Timeout.queuereturn=seconds Set the timeout on undelivered messages in the queue to the specified time. After delivery has failed (e.g., because of a host being down) for this amount of time, failed messages will be returned to the sender. The default is five days.
UserDatabaseSpec=userdatabase If set, a user database is consulted to get forwarding information. You can consider this an adjunct to the aliasing mechanism, except that the database is intended to be distributed; aliases are local to a particular host. This may not be available if your sendmail does not have the USERDB option compiled in.
ForkEachJob Fork each job during queue runs. May be convenient on memory poor machines.
SevenBitInput Strip incoming messages to seven bits.
EightBitMode=mode Set the handling of eight bit input to seven bit destinations to mode: m (mimefy) will convert to seven-bit MIME format, p (pass) will pass it as eight bits (but violates protocols), and s (strict) will bounce the message.
MinQueueAge=seconds Sets how long a job must ferment in the queue between attempts to send it.
DefaultCharSet=charset Sets the default character set used to label 8-bit data that is not otherwise labelled.
DialDelay=sleeptime If opening a connection fails, sleep for sleeptime seconds and try again. Useful on dial-on-demand sites.
NoRecipientAction=action when there are no recipient headers (To:, Cc: or Bcc:) in the message
none leaves the message unchanged
add-to adds a To: header with the envelope recipients,
add-apparently-to adds an Apparently-To: header with the envelope recipients, add-bcc adds an empty Bcc: header, and add to-undisclosed adds a header reading `To: undisclosed-recipients:;'.
MaxDaemonChildren=N Sets the maximum number of children that an incoming SMTP daemon will allow to spawn at any time to N.
ConnectionRateThrottle=N Sets the maximum number of connections per second to the SMTP port to N.
In aliases, the first character of a name may be a vertical bar to cause interpretation of the rest of the name as a command to pipe the mail to. It may be necessary to quote the name to keep sendmail from suppressing the blanks from between arguments. For example, a common alias is: msgs: "|/usr/bin/msgs -s" Aliases may also have the syntax ``:include:filename'' to ask sendmail to read the named file for a list of recipients. For example, an alias such as: poets: ":include:/usr/local/lib/poets.list" would read /usr/local/lib/poets.list for the list of addresses making up the group. Sendmail returns an exit status describing what it did. The codes are defined in :
EX_OK Successful completion on all addresses.
EX_NOUSER User name not recognized.
EX_UNAVAILABLE Catchall meaning necessary resources were not available.
EX_SYNTAX Syntax error in address.
EX_SOFTWARE Internal software error, including bad arguments.
EX_OSERR Temporary operating system error, such as ``cannot fork''.
EX_NOHOST Host name not recognized.
EX_TEMPFAIL Message could not be sent immediately, but was queued.

/usr/lib/sendmail -t -n Read message for recipients. no aliasing.

If invoked as


75 sendmail: fatal: dgerman(501): Recipient addresses must be specified on the command line or via the -t option
?? an not chdir(/var/spool/mqueue/): Permission denied
?? Program mode requires special privileges, e.g., root or TrustedUser.
sendmail gets blamed for problems such as overly permissive modes on directories, so it checks various system directories and files. Don't turn this off by setting DontBlameSendmail Dont Blame sendmail


/etc/mail/ overides these defaults:
/var/spool/mqueue/* # temo files


mail(1), syslog(3), aliases(5), mailaddr(7), mail.local(8), rc(8), rmail(8)