SENDMAIL(ADMN) UNIX System V
Name
sendmail - send mail over the internet
Syntax
/usr/lib/sendmail [ flags ] [ address ... ]
newaliases
mailq [ -v ]
Description
sendmail sends a message to one or more recipients, routing
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
appropriately. Aliasing can be prevented by preceding the
address with a backslash. Normally, the sender is not
included in any alias expansions; for instance, if `john'
sends to `group', and `group' includes `john' in the
expansion, then the letter will not be delivered to `john'.
Flags are:
-ba Go into ARPANET mode. Every input line must end
with a CR-LF, and each message 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. sendmail will fork and run in
background listening on TCP port 25 for incoming
SMTP connections. This is normally run from
/etc/rc.
-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 SMTP.
-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 bypassed.
-dX Set debugging value to X.
-Ffullname Set the full name of the sender.
-fname Sets the name of the ``from'' person (that is,
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 message, 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] 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, `h'
being hours, `d' being days, and `w' being
weeks. For example, ``-q1h30m'' or ``-q90m''
would both set the timeout to one hour and
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, and so on.
There is 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 TCP/IP Administrator's Guide.
The options are:
Afile Use alternate alias file.
c On mailers that are considered expensive to
connect to, do not initiate immediate
connection. This requires queueing.
dx Set the delivery mode to x. Delivery modes are
`i' for interactive (synchronous) delivery, `b'
for background (asynchronous) delivery, and `q'
for queue only - that is, actual delivery is
done the next time the queue is run.
D Try to rebuild the alias database automatically
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 (so that 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 mode `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.
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.
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 (that is, commas instead of
spaces between addresses). If set, an adaptive
algorithm is used that will correctly determine
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, so 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 delivery.
Ttime Set the timeout on undelivered messages in the
queue to the specified time. After delivery has
failed (for instance, because a host is down)
for this amount of time, failed messages will be
returned to the sender. The default is three
days.
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 which to pipe the mail. It may be necessary to
quote the name to keep sendmail from suppressing the blanks
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:
poets: ":include:/usr/local/lib/poets.list"
would read /usr/local/lib/poets.list for the list of
addresses making up the group.
The sendmail command returns an exit status describing what
it did. The codes are defined in <sysexits.h>:
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. This works only if sendmail was built with a DBM
library. Otherwise, this option does nothing. If invoked as
mailq, sendmail will print the contents of the mail queue.
Files
Except for /usr/lib/sendmail.cf, these pathnames are all
specified in /usr/lib/sendmail.cf. Thus, these values are
only approximations.
/usr/lib/aliases raw data for alias names
/usr/lib/sendmail.cf configuration file
/usr/lib/sendmail.fc frozen configuration
/usr/lib/sendmail.hf help file
/usr/lib/sendmail.st collected statistics
/usr/spool/mqueue/* temp files
See Also
mail(TC), aliases(SFF), mailaddr(SFF);
RFC819, RFC821, RFC822;
The chapter ``Introduction to sendmail'' in the TCP/IP
Administrator's Guide;
The chapter ``Installing and Operating Sendmail'' in the
TCP/IP Administrator's Guide.
(printed 8/31/90) SENDMAIL(ADMN)