sendmail - an electronic mail transport agent
sendmail [flags] [address ...] [-v]
Sendmail sends a message to one or more recipients, routing
over whatever networks are necessary. Sendmail does internetwork forwarding
as necessary to deliver the message to the correct
Sendmail is not intended as a user interface routine; other
user-friendly front ends; sendmail is used only to deliver pre-formatted
With no flags, sendmail reads its standard input up to an
a line consisting only of a single dot and sends a copy of
found there to all of the addresses listed. It determines
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
with 8.10, the sender is included in any alias expansions, e.g.,
if `john' sends to `group', and `group' includes `john' in
then the letter will also be delivered to `john'.
Parameters [Toc] [Back]
-Ac Use submit.cf even if the operation mode does
not indicate an
initial mail submission.
-Am Use sendmail.cf even if the operation mode indicates an initial
-Btype Set the body type to type. Current legal values
are 7BIT or
-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
the name of the sender.
-bd Run as a daemon. Sendmail will fork and run in
listening on socket 25 for incoming SMTP
By default, Sendmail will also listen on socket
587 for RFC
2476 message submission. This is normally run
-bD Same as -bd except runs in foreground.
-bh Print the persistent host status database.
-bH Purge expired entries from the persistent host
-bi Initialize the alias database.
-bm Deliver mail in the usual way (default).
-bp Print a listing of the queue(s).
-bP Print number of entries in the queue(s); only
shared memory support.
-bs Use the SMTP protocol as described in RFC 821 on
and output. This flag implies all the operations of the
-ba flag that are compatible with SMTP.
-bt Run in address test mode. This mode reads addresses and
shows the steps in parsing; it is used for debugging configuration
-bv Verify names only - do not try to collect or deliver a message.
Verify mode is normally used for validating users or
-Cfile Use alternate configuration file. Sendmail
gives up any enhanced
(set-user-ID or set-group-ID) privileges
if an alternate
configuration file is specified.
-D logfile Send debugging output to the indicated log file
Set the debugging flag for category to level.
is either an integer or a name specifying the
level is an integer specifying the level of debugging output
desired. Higher levels generally mean more output. More
than one flag may be specified by separating
flags with commas.
A list of numeric debugging categories can
be found in
the TRACEFLAGS file in the sendmail source distribution.
The option -d0.1 prints the version of sendmail
and the options
it was compiled with.
Most other categories are only useful with, and
in, sendmail 's source code.
-Ffullname Set the full name of the sender.
-fname Sets the name of the ``from'' person (i.e., the
sender of the mail). This address may also be
used in the
From: header if that header is missing during
The envelope sender address is used as
for delivery status notifications and may also
appear in a
Return-Path: header. -f should only be used by
users (normally root, daemon, and network) or if
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 Relay (gateway) submission of a message, e.g.,
-hN Set the hop count to N. The hop count is incremented every
time the mail is processed. When it reaches a
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.
This should be set if you are reading
data from a
-L tag Set the identifier used in syslog messages to
-N dsn Set delivery status notification conditions to
dsn, which can
be `never' for no notifications or a comma separated list of
the values `failure' to be notified if delivery
`delay' to be notified if delivery is delayed,
to be notified when the message is successfully
-n Don't do aliasing.
Set option option to the specified value. This
long names. See below for more details.
-ox value Set option x to the specified value. This form
character names only. The short names are not
this manual page; see the Sendmail Installation
Guide for details.
-pprotocol Set the name of the protocol used to receive the
This can be a simple protocol name such as
``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
`h' being hours, `d' being days, and `w'
For example, `-q1h30m' or `-q90m' would both set
to one hour thirty minutes. By default,
sendmail will run in
the background. This option can be used safely
-qp[time] Similar to -qtime, except that instead of periodically forking
a child to process the queue, sendmail forks
persistent child for each queue that alternates
the queue and sleeping. The sleep time
is given as
the argument; it 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
but run in the foreground.
-qG name Process jobs in queue group called name only.
Limit processed jobs to those containing substr
as a substring
of the queue ID or not when ! is specified.
Limit processed jobs to quarantined jobs containing substr as
a substring of the quarantine reason or not when
! is specified.
Limit processed jobs to those containing substr
as a substring
of one of the recipients or not when ! is
Limit processed jobs to those containing substr
as a substring
of the sender or not when ! is specified.
Quarantine a normal queue items with the given
reason or unquarantine
quarantined queue items if no reason
This should only be used with some sort of item
as described above.
-R return Set the amount of the message to be returned if
bounces. The return parameter can be `full' to
entire message or `hdrs' to return only the
headers. In the
latter case also local bounces return only the
-rname An alternate and obsolete form of the -f flag.
-t Read message for recipients. To:, Cc:, and Bcc:
be scanned for recipient addresses. The Bcc:
line will be
deleted before transmission.
-V envid Set the original envelope id. This is propagated across SMTP
to servers that support DSNs and is returned in
-v Go into verbose mode. Alias expansions will be
-X logfile Log all traffic in and out of mailers in the indicated log
file. This should only be used as a last resort
mailer bugs. It will log a lot of data
-- Stop processing command flags and use the rest
of the arguments
Options [Toc] [Back]
There are also a number of processing options that may be
these will only be used by a system administrator. Options
may be set
either on the command line using the -o flag (for short
names), the -O
flag (for long names), or in the configuration file. This
is a 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 (and
consult the Sendmail Installation and Operation Guide. The
Use alternate alias file.
On mailers that are considered ``expensive'' to
don't initiate immediate connection. This requires queueing.
Checkpoint the queue file after every N successful deliveries
(default 10). This avoids excessive duplicate
when sending to long mailing lists interrupted
Set the delivery mode to x. Delivery modes are
`i' for interactive
(synchronous) delivery, `b' for background (asynchronous)
delivery, `q' for queue only - i.e.,
is done the next time the queue is run, and
`d' for deferred
- the same as `q' except that database
maps which have set the -D option (default for
the host map)
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
to the file dead.letter in the sender's home directory.
Save UNIX-style From lines at the front of messages.
The maximum number of times a message is allowed
before we decide it is in a loop.
IgnoreDots Do not take dots on a line by themselves as a
Send error messages in MIME format. If not set,
the DSN (Delivery
Status Notification) SMTP extension is
Set connection cache timeout.
Set connection cache size.
LogLevel=n The log level.
Don't send to ``me'' (the sender) if I am in an
Validate the right hand side of aliases during a
If set, this message may have old style headers.
If not set,
this message is guaranteed to have new style
commas instead of spaces between addresses). If
adaptive algorithm is used that will correctly
header format in most cases.
Select the directory in which to queue messages.
Save statistics in the named file.
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,
will be returned to the sender. The default is
If set, a user database is consulted to get forwarding information.
You can consider this an adjunct to the
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
option compiled in.
Fork each job during queue runs. May be convenient on memory-poor
Strip incoming messages to seven bits.
Set the handling of eight bit input to seven bit
to mode: m (mimefy) will convert to seven-bit
MIME format, p
(pass) will pass it as eight bits (but violates
and s (strict) will bounce the message.
Sets how long a job must ferment in the queue
to send it.
Sets the default character set used to label
8-bit data that
is not otherwise labelled.
If opening a connection fails, sleep for
and try again. Useful on dial-on-demand sites.
Set the behaviour when there are no recipient
Cc: or Bcc:) in the message to action: none
leaves the message
unchanged, add-to adds a To: header with
recipients, add-apparently-to adds an Apparently-To: header
with the envelope recipients, add-bcc adds an
header, and add-to-undisclosed adds a header
Sets the maximum number of children that an incoming SMTP
daemon will allow to spawn at any time to 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
the blanks from between arguments. For example, a common
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
would read /usr/local/lib/poets.list for the list of addresses making up
Sendmail returns an exit status describing what it did. The
defined in <sysexits.h>:
EX_OK Successful completion on all addresses.
EX_NOUSER User name not recognized.
EX_UNAVAILABLE Catchall meaning necessary resources
EX_SYNTAX Syntax error in address.
EX_SOFTWARE Internal software error, including bad
EX_OSERR Temporary operating system error, such
EX_NOHOST Host name not recognized.
EX_TEMPFAIL Message could not be sent immediately,
If invoked as newaliases, sendmail will rebuild the alias
invoked as mailq, sendmail will print the contents of the
mail queue. If
invoked as hoststat, sendmail will print the persistent host
database. If invoked as purgestat, sendmail will purge expired entries
from the persistent host status database.
sendmail often gets blamed for many problems that are actually the result
of other problems, such as overly permissive modes on directories. For
this reason, sendmail checks the modes on system directories
and files to
determine if they can be trusted. Although these checks can
off and your system security reduced by setting the DontBlameSendmail option,
the permission problems should be fixed. For more information,
Except for the file /etc/mail/sendmail.cf itself the following pathnames
are all specified in /etc/mail/sendmail.cf. Thus, these
values are only
/etc/mail/aliases raw data for alias names
/etc/mail/aliases.db data base of alias names
/etc/mail/sendmail.cf configuration file
/etc/mail/sendmail.hf help file
/var/log/sendmail.st collected statistics
/var/spool/mqueue/* temp files
mail(1), syslog(3), aliases(5), mailer.conf(5), mailaddr(7),
mail.local(8), mailq(8), newaliases(8), rc(8), rmail(8)
DARPA Internet Request For Comments RFC 819, RFC 821, RFC
"Sendmail Installation and Operation Guide",
"Sendmail - An Internetwork Mail Router",
"Filtering Mail with Sendmail",
The sendmail command appeared in 4.2BSD.
OpenBSD 3.6 December 1, 2003
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