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sendmail - an electronic mail transport agent
sendmail [flags] [address ...]
Sendmail sends a message to one or more recipients, rout-
ing the message over whatever networks 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 addresses.
Local addresses are looked up in a file and aliased appro-
priately. Aliasing can be prevented by preceding the
address with a backslash. Beginning with 8.10, 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'.
-Btype Set the body type to type. Current legal values
are 7BIT or 8BITMIME.
-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
-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 normally run from /etc/rc.
-bD Same as -bd except runs in foreground.
-bh Print the persistent host status database.
-bH Purge expired entries from the persistent host
Date: 2000/02/01 05:49:57 1
-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
-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.
-Cfile Use alternate configuration file. Sendmail refuses
to run as root if an alternate configuration file
-dX Set debugging value to X.
Set the full name of the sender.
-fname Sets the name of the ``from'' person (i.e., the
envelope sender of the mail). 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 deliv-
ery status notifications and may also appear in a
Return-Path: header. -f should only be used by
``trusted'' users (normally root, daemon, and net-
work) 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
-hN Set the hop count to N. The hop count is incre-
mented 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
-i Ignore dots alone on lines by themselves in incom-
ing messages. This should be set if you are read-
ing data from a file.
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-L tag Set the identifier used in syslog messages to the
-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 failed, `delay' to be notified
if delivery is delayed, and `success' to be noti-
fied when the message is successfully delivered.
-n Don't do aliasing.
Set option option to the specified value. This
form uses long names. See below for more details.
Set option x to the specified value. This form
uses single character names only. The short names
are not described in this manual page; see the
Sendmail Installation and Operation Guide for
Set the name of the protocol used to receive the
message. This can be a simple protocol name such
as ``UUCP'' or a protocol and hostname, such as
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 seconds, `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 the background. This option
can be used safely with -bd.
Limit processed jobs to those containing substr as
a substring of the queue id.
Limit processed jobs to those containing substr as
a substring of one of the recipients.
Limit processed jobs to those containing substr as
a substring of the sender.
Set the amount of the message to be returned if the
Date: 2000/02/01 05:49:57 3
message bounces. The return parameter can be
`full' to return the entire message or `hdrs' to
return only the headers. In the latter case also
local bounces return only the headers.
-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.
-U Initial (user) submission. This should always be
set when called from a user agent such as Mail or
exmh and never be set when called by a network
delivery agent such as rmail.
Set the original envelope id. This is propagated
across SMTP to servers that support DSNs and is
returned in DSN-compliant error messages.
-v Go into verbose mode. Alias expansions will be
Log all traffic in and out of mailers in the indi-
cated log file. This should only be used as a last
resort for debugging mailer bugs. It will log a
lot of data very quickly.
-- Stop processing command flags and use the rest of
the arguments as addresses.
There are also a number of processing options that may be
set. Normally these will only be used by a system admin-
istrator. 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 details), consult the Sendmail Instal-
lation and Operation Guide. The options are:
Use alternate alias file.
On mailers that are considered ``expensive'' to
connect to, don't initiate immediate connection.
This requires queueing.
Checkpoint the queue file after every N successful
Date: 2000/02/01 05:49:57 4
deliveries (default 10). This avoids excessive
duplicate deliveries when sending to long mailing
lists interrupted by system crashes.
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., 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)
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 directory.
Save UNIX-style From lines at the front of mes-
The maximum number of times a message is allowed to
``hop'' before we decide it is in a loop.
Do not take dots on a line by themselves as a mes-
Send error messages in MIME format. If not set,
the DSN (Delivery Status Notification) SMTP exten-
sion is disabled.
Set connection cache timeout.
Set connection cache size.
The log level.
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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 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.
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, failed messages will be
returned to the sender. The default is five days.
If set, a user database is consulted to get for-
warding 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 avail-
able if your sendmail does not have the USERDB
option compiled in.
Fork each job during queue runs. May be convenient
on memory-poor machines.
Strip incoming messages to seven bits.
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.
Sets how long a job must ferment in the queue
Date: 2000/02/01 05:49:57 6
between attempts 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 sleeptime
seconds and try again. Useful on dial-on-demand
Set the behaviour when there are no recipient head-
ers (To:, Cc: or Bcc:) in the message to action:
none leaves the message unchanged, add-to adds a
To: header with the envelope recipients, add-appar-
ently-to adds an Apparently-To: header with the
envelope recipients, add-bcc adds an empty Bcc:
header, and add-to-undisclosed adds a header read-
ing `To: undisclosed-recipients:;'.
Sets the maximum number of children that an incom-
ing SMTP daemon will allow to spawn at any time to
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 verti-
cal 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
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 recipi-
ents. 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 <sysexits.h>:
EX_OK Successful completion on all addresses.
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User name not recognized.
Catchall meaning necessary resources were not
Syntax error in address.
Internal software error, including bad arguments.
Temporary operating system error, such as ``cannot
Host name not recognized.
Message could not be sent immediately, but was
If invoked as newaliases, sendmail will rebuild the alias
database. If invoked as mailq, sendmail will print the
contents of the mail queue. If invoked as hoststat, send-
mail will print the persistent host status database. If
invoked as purgestat, sendmail will purge expired entries
from the persistent host status database. If invoked as
smtpd, sendmail will act as a daemon, as if the -bd option
sendmail often gets blamed for many problems that are
actually the result of other problems, such as overly per-
missive modes on directories. For this reason, sendmail
checks the modes on system directories and files to deter-
mine if they can be trusted. Although these checks can be
turned off and your system security reduced by setting the
DontBlameSendmail option, the permission problems should
be fixed. For more information, see:
Except for the file /etc/mail/sendmail.cf itself the fol-
lowing pathnames are all specified in /etc/mail/send-
mail.cf. Thus, these values are only approximations.
raw data for alias names
Date: 2000/02/01 05:49:57 8
data base of alias names
binmail(1), mail(1), rmail(1), syslog(3), aliases(5),
DARPA Internet Request For Comments RFC819, RFC821,
RFC822. Sendmail - An Internetwork Mail Router, No. 9,
SMM. Sendmail Installation and Operation Guide, No. 8,
The sendmail command appeared in 4.2BSD.
Date: 2000/02/01 05:49:57 9