sendmail - send mail over the internet
/usr/sbin/sendmail [ flags ] [ address ... ]
mailq [ -v ]
Sendmail sends a message to one or more recipients, routing the message over whatever net-
works are necessary. Sendmail does internetwork forwarding as necessary to deliver the
message to the correct place.
Sendmail is not intended as a user interface routine; other programs provide user-friendly
front ends; sendmail is used only to deliver pre-formatted 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
Local addresses are looked up in a file and aliased appropriately. Aliasing can be pre-
vented by preceding the address with a backslash. Normally the sender is not included in
any alias expansions, e.g., if `john' sends to `group', and `group' includes `john' in the
expansion, then the letter will not be delivered to `john'.
-ba Go into ARPANET mode. All input lines must end with a CR-LF, and all messages
will be generated with a CR-LF at the end. Also, the ``From:'' and
``Sender:'' fields are examined for the name of the sender.
-bd Run as a daemon. This requires Berkeley IPC. Sendmail will fork and run in
background listening on socket 25 for incoming SMTP connections. This is nor-
mally run from /etc/rc.
-bi Initialize the alias database.
-bm Deliver mail in the usual way (default).
-bp Print a listing of the queue.
-bs Use the SMTP protocol as described in RFC821 on standard input and output.
This flag implies all the operations of the -ba flag that are compatible with
-bt Run in address test mode. This mode reads addresses and shows the steps in
parsing; it is used for debugging configuration tables.
-bv Verify names only - do not try to collect or deliver a message. Verify mode
is normally used for validating users or mailing lists.
-bz Create the configuration freeze file.
-Cfile Use alternate configuration file. Sendmail refuses to run as root if an
alternate configuration file is specified. The frozen configuration file is
-dX Set debugging value to X.
-Ffullname Set the full name of the sender.
-fname Sets the name of the ``from'' person (i.e., the sender of the mail). -f can
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.
-hN Set the hop count to N. The hop count is incremented every time the mail is
processed. When it reaches a limit, the mail is returned with an error mes-
sage, the victim of an aliasing loop. If not specified, ``Received:'' lines
in the message are counted.
-n Don't do aliasing.
-oxvalue Set option x to the specified value. Options are described below.
-q[time] Processed 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 sec-
onds, `m' being minutes, `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. If time is specified, sendmail will run in background. This
option can be used safely with -bd.
-rname An alternate and obsolete form of the -f flag.
-t Read message for recipients. To:, Cc:, and Bcc: lines will be scanned for
recipient addresses. The Bcc: line will be deleted before transmission. Any
addresses in the argument list will be suppressed, that is, they will not
receive copies even if listed in the message header.
-v Go into verbose mode. Alias expansions will be announced, etc.
There are also a number of processing options that may be set. Normally these will only
be used by a system administrator. Options may be set either on the command line using
the -o flag or in the configuration file. These are described in detail in the Sendmail
Installation and Operation Guide. The options are:
Afile Use alternate alias file.
c On mailers that are considered ``expensive'' to connect to, don't initiate
immediate connection. This requires queueing.
dx Set the delivery mode to x. Delivery modes are `i' for interactive (synchro-
nous) delivery, `b' for background (asynchronous) delivery, and `q' for queue
only - i.e., actual delivery is done the next time the queue is run.
D Try to automatically rebuild the alias database if necessary.
ex Set error processing to mode x. Valid modes are `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
Fmode The mode to use when creating temporary files.
f Save UNIX-style From lines at the front of messages.
gN The default group id to use when calling mailers.
Hfile The SMTP help file.
i Do not take dots on a line by themselves as a message terminator.
Ln The log level.
m Send to ``me'' (the sender) also if I am in an alias expansion.
o 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 deter-
mine the header format in most cases.
Qqueuedir Select the directory in which to queue messages.
rtimeout The timeout on reads; if none is set, sendmail will wait forever for a mailer.
This option violates the word (if not the intent) of the SMTP specification,
show the timeout should probably be fairly large.
Sfile Save statistics in the named file.
s Always instantiate the queue file, even under circumstances where it is not
strictly necessary. This provides safety against system crashes during deliv-
Ttime 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 three
tstz,dtz Set the name of the time zone.
uN Set the default user id for mailers.
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/ucb/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:
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 <sysex-
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.
If invoked as newaliases, sendmail will rebuild the alias database. If invoked as mailq,
sendmail will print the contents of the mail queue.
Except for /etc/sendmail.cf, these pathnames are all specified in /etc/sendmail.cf. Thus,
these values are only approximations.
/etc/aliases raw data for alias names
/etc/aliases.dir data base of alias names
/etc/sendmail.cf configuration file
/etc/sendmail.fc frozen configuration
/usr/share/misc/sendmail.hf help file
/var/log/sendmail.st collected statistics
/usr/spool/mqueue/* temp files
mail(1), rmail(1), syslog(3), aliases(5), sendmail.cf(5), mailaddr(7), rc(8);
DARPA Internet Request For Comments RFC819, RFC821, RFC822;
Sendmail - An Internetwork Mail Router (SMM:16);
Sendmail Installation and Operation Guide (SMM:7)
4th Berkeley Distribution October 23, 1996 SENDMAIL(8)