sendmail(1M) Maintenance Commands sendmail(1M)
NAME
sendmail - send mail over the internet
SYNOPSIS
/usr/lib/sendmail [ -ba ] [ -bd ] [ -bi ] [ -bm ] [ -bp ]
[ -bs ] [ -bt ] [ -bv ] [ -B type ] [ -C file ]
[ -d X ] [ -F fullname ] [ -f name ] [ -h N ] [ -M id ]
[ -n ] [ -o xvalue ] [ -p protocol ] [ -q [ time ] ]
[ -q Xstring ] [ -r name ] [ -t ] [ -v ] [ -X logfile
]
[ address ... ]
AVAILABILITY
SUNWcsu
DESCRIPTION
sendmail sends a message to one or more people, 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
EOF, or a line with a single dot, and sends a copy of the
letter found there to all of the addresses listed. It
determines the network to use based on the syntax and con-
tents of the addresses.
Local addresses are looked up in the local aliases(4) file,
or by using the YP name service, and aliased appropriately.
In addition, if there is a .forward file in a recipient's
home directory, sendmail forwards a copy of each message to
the list of recipients that file contains. Aliasing can be
prevented by preceding the address with a backslash. Nor-
mally the sender is not included in alias expansions, for
example, if `john' sends to `group', and `group' includes
`john' in the expansion, then the letter will not be
delivered to `john'.
sendmail will also route mail directly to other known hosts
in a local network. The list of hosts to which mail is
directly sent is maintained in the file /usr/lib/mailhosts.
If a letter is found to be undeliverable, it is returned to
the sender with diagnostics that indicate the location and
nature of the failure; or, the letter is placed in a
dead.letter file in the sender's home directory.
OPTIONS
-ba Go into ARPANET mode. All input lines must
end with a RETURN-LINEFEED, and all messages
will be generated with a RETURN-LINEFEED at
the end. Also, the From: and Sender: fields
are examined for the name of the sender.
-bd Run as a daemon, waiting for incoming SMTP
connections.
-bi Initialize the aliases(4) database.
-bm Deliver mail in the usual way (default).
-bp Print a summary of the mail queue.
-bs Use the SMTP protocol as described in RFC
821. 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.
-B type indicate body type (7BIT or 8BITMIME)
-C file Use alternate configuration file.
-d X Set debugging value to X.
-F fullname Set the full name of the sender.
-f name Sets the name of the "from" person (that is,
the sender of the mail). -f can only be used
by "trusted" users (who are listed in the
configuration file).
-h N 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.
-M id Attempt to deliver the queued message with
message-id id. This option is supported for
backward compatibility and the -qI option is
preferred.
-n Do not do aliasing.
-o xvalue Set option x to the specified value. Pro-
cessing Options are described below.
-p protocol Set the sending protocol. Programs are
encouraged to set this. The protocol field
can be in form protocol:host to set both the
sending protocol and the sending host. For
example:
-pUUCP:uunet
sets the sending protocol to UUCP and the
sending host to uunet. (Some existing pro-
grams use -oM to set the r and s macros; this
is equivalent to using -p).
-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 thirty
minutes.
-q Xstring Run the queue once, limiting the jobs to
those matching Xstring. The key letter X can
be:
I to limit based on queue identifier (see
-M option).
R to limit based on recipient (see -R
option).
S to limit based on sender.
A particular queued job is accepted if one of
the corresponding addresses contains the
indicated string.
-r name An alternate and obsolete form of the -f
flag.
-R string Go through the queue of pending mail and
attempt to deliver any message with a reci-
pient containing the specified string. This
is useful for clearing out mail directed to a
machine which has been down for awhile. This
option is supported for backward compatibil-
ity and the -qR option is preferred.
-t Read message for recipients. To:, Cc:, and
Bcc: lines will be scanned for people to
send to. The Bcc: line will be deleted
before transmission. Any addresses in the
argument list will be suppressed.
-v Go into verbose mode. Alias expansions will
be announced, etc.
-X logfile Log all traffic in and out of sendmail in the
indicated logfile for debugging mailer prob-
lems. This produces a lot of data very
quickly and should be used sparingly.
Processing Options
There are a number of "random" options that can be set from
a configuration file. Options are represented by single
characters. The syntax of this line is:
Oovalue
This sets option o to be value. Depending on the option,
value may be
+o a string
+o an integer
+o a boolean (with legal values t, T, f, or F;
the default is TRUE)
+o a time interval.
The options supported are:
aN If set, wait up to N minutes for an "@:@"
entry to exist in the aliases(4) database
before starting up. If it does not appear in
N minutes, rebuild the database (if the D
option is also set) or issue a warning.
Afile Specify possible alias file(s).
bN/M Insist on at least N blocks free on the
filesystem that holds the queue files before
accepting email via SMTP. If there is insuf-
ficient space sendmail gives a 452 response
to the MAIL command. This invites the sender
to try again later. The optional M is a max-
imum message size advertised in the ESMTP
EHLO response. It is currently otherwise
unused.
Bc Set the blank substitution character to c.
Unquoted spaces in addresses are replaced by
this character. Defaults to SPACE (i.e., no
change is made).
c If an outgoing mailer is marked as being
expensive, don't connect immediately.
CN Checkpoints the queue every N (default 10)
addresses sent. If your system crashes dur-
ing delivery to a large list, this prevents
retransmission to any but the last N reci-
pients.
dx Deliver in mode x. Legal modes are:
i Deliver interactively (synchro-
nously)
b Deliver in background (asynchro-
nously)
q Just queue the message (deliver
during queue run)
Defaults to b if no option is specified, i if
it is specified but given no argument (i.e.,
Od is equivalent to Odi).
D If set, rebuild the /etc/mail/aliases data-
base if necessary and possible. If this
option is not set, sendmail will never
rebuild the aliases database unless expli-
citly requested using -bi, or newaliases(1)
is invoked.
ex Dispose of errors using mode x. The values
for x are:
p Print error messages (default)
q No messages, just give exit status
m Mail back errors
w Write back errors (mail if user not
logged in)
e Mail back errors and give zero exit
stat always
Efile/message Prepend error messages with the indicated
message. If it begins with a slash, it is
assumed to be the pathname of a file contain-
ing a message (this is the recommended set-
ting). Otherwise, it is a literal message.
The error file might contain the name, email
address, and/or phone number of a local
postmaster who could provide assistance in to
end users. If the option is missing or null,
or if it names a file which does not exist or
which is not readable, no message is printed.
f Save Unix-style From lines at the front of
headers. Normally they are assumed redundant
and discarded.
Fmode The file mode for queue files.
gn Set the default group ID for mailers to run
in to n. Defaults to 1. The value can also
be given as a symbolic group name.
hN The maximum hop count. Messages that have
been processed more than N times are assumed
to be in a loop and are rejected. Defaults
to 25.
Hfile Specify the help file for SMTP.
i Ignore dots in incoming messages. This is
always disabled (that is, dots are always
accepted) when reading SMTP mail.
I Insist that the name server be running to
resolve host names. If this is not set and
the name server is not running, the
/etc/hosts file (see hosts(4)) will be con-
sidered complete. In general, you do want to
set this option if your /etc/hosts file does
not include all hosts known to you or if you
are using the MX (mail forwarding) feature of
the name server. The name server will still
be consulted even if this option is not set,
but sendmail will feel free to resort to
reading /etc/hosts if the name server is not
available. Thus, you should never set this
option if you do not run the name server.
j If set, send error messages in MIME format
(see RFC1341 and RFC1344 for details).
Jpath Set the path for searching for users' .for-
ward files. The default is $z/.forward.
Some sites that use the automounter may
prefer to change this to /var/forward/$u to
search a file with the same name as the user
in a system directory. It can also be set to
a sequence of paths separated by colons;
sendmail stops at the first file it can
successfully and safely open. For example,
/var/forward/$u:$z/.forward will search first
in /var/forward/ username and then in
~username/.forward (but only if the first
file does not exist).
kN The maximum number of open connections that
will be cached at a time. The default is
one. This delays closing the current connec-
tion until either this invocation of sendmail
needs to connect to another host or it ter-
minates. Setting it to zero defaults to the
old behavior, that is, connections are closed
immediately.
Ktimeout The maximum amount of time a cached connec-
tion will be permitted to idle without
activity. If this time is exceeded, the con-
nection is immediately closed. This value
should be small (on the order of ten
minutes). Before sendmail uses a cached con-
nection, it always sends a NOOP (no opera-
tion) command to check the connection; if
this fails, it reopens the connection. This
keeps your end from failing if the other end
times out. The point of this option is to be
a good network neighbor and avoid using up
excessive resources on the other end. The
default is five minutes.
l If there is an Errors-To: header, send error
messages to the addresses listed there. They
normally go to the envelope sender. Use of
this option causes sendmail to violate RFC
1123.
Ln Set the default log level to n. Defaults to
9.
m Send to me too, even if I am in an alias
expansion.
Mxvalue Set the macro x to value. This is intended
only for use from the command line.
n Validate the RHS of aliases when rebuilding
the aliases(4) database.
o Assume that the headers may be in old format,
i.e., spaces delimit names. This actually
turns on an adaptive algorithm: if any reci-
pient address contains a comma, parenthesis,
or angle bracket, it will be assumed that
commas already exist. If this flag is not
on, only commas delimit names. Headers are
always output with commas between the names.
Ooptions Set server SMTP options. The options are
key=value pairs. Known keys are:
Port Name/number of listening port
(defaults to smtp)
Addr Address mask (defaults INADDR_ANY)
Family Address family (defaults to INET)
Listen Size of listen queue (defaults to
10)
The Address mask may be a numeric address in
dot notation or a network name.
popt,opt,... Set the privacy options. ``Privacy'' is
really a misnomer; many of these are just a
way of insisting on stricter adherence to the
SMTP protocol. The options can be selected
from:
public Allow open access
needmailhelo Insist on HELO or EHLO
command before MAIL
needexpnhelo Insist on HELO or EHLO
command before EXPN
noexpn Disallow EXPN entirely
needvrfyhelo Insist on HELO or EHLO
command before VRFY
novrfy Disallow VRFY entirely
restrictmailq Restrict mailq command
restrictqrun Restrict -q command line
flag
goaway Disallow essentially all
SMTP status queries
authwarnings Put X-Authentication-
Warning: headers in mes-
sages
The goaway pseudo-flag sets all flags except
restrictmailq and restrictqrun. If mailq is
restricted, only people in the same group as
the queue directory can print the queue. If
queue runs are restricted, only root and the
owner of the queue directory can run the
queue. Authentication Warnings add warnings
about various conditions that may indicate
attempts to spoof the mail system, such as
using an non-standard queue directory.
Ppostmaster If set, copies of error messages will be sent
to the named postmaster. Only the header of
the failed message is sent. Since most
errors are user problems, this is probably
not a good idea on large sites, and arguably
contains all sorts of privacy violations, but
it seems to be popular with certain operating
systems vendors.
qfactor Use factor as the multiplier in the map func-
tion to decide when to just queue up jobs
rather than run them. This value is divided
by the difference between the current load
average and the load average limit (x flag)
to determine the maximum message priority
that will be sent. Defaults to 600000.
Qdir Use the named dir as the queue directory.
r timeouts Timeout reads after time interval. The
timeouts argument is a list of keyword=value
pairs. The recognized timeouts and their
default values, and their minimum values
specified in RFC 1123 section 5.3.2 are:
initial wait for initial greeting
message [5m, 5m]
helo reply to HELO or EHLO
command [5m, none]
mail reply to MAIL command
[10m, 5m]
rcpt reply to RCPT command
[1h, 5m]
datainit reply to DATA command
[5m, 2m]
datablock data block read [1h, 3m]
datafinal reply to final ``.'' in
data [1h, 10m]
rset reply to RSET command
[5m, none]
quit reply to QUIT command
[2m, none]
misc reply to NOOP and VERB
commands [2m, none]
command command read [1h, 5m]
ident IDENT protocol timeout
[30s, none]
All but command apply to client SMTP. For
backward compatibility, a timeout with no
keyword= part will set all of the longer
values.
s Be super-safe when running things, i.e.,
always instantiate the queue file, even if
you are going to attempt immediate delivery.
sendmail always instantiates the queue file
before returning control the client under any
circumstances.
Sfile Log statistics in the named file.
ttzinfo Set the local time zone info to tzinfo - for
example, "PST8PDT ." Actually, if this is
not set, the TZ environment variable is
cleared (so the system default is used); if
set but null, the user's TZ variable is used,
and if set and non-null the TZ variable is
set to this value.
Trtime/wtime Set the queue timeout to rtime. After this
interval, messages that have not been suc-
cessfully sent will be returned to the
sender. Defaults to five days (5d). The
optional wtime is the time after which a
warning message is sent. If it is missing or
zero then no warning messages are sent.
un Set the default userid for mailers to n.
Mailers without the S flag in the mailer
definition will run as this user. Defaults
to 1. The value can also be given as a sym-
bolic user name.
v Run in verbose mode. If this is set, send-
mail adjusts options c (don't connect to
expensive mailers) and d (delivery mode) so
that all mail is delivered completely in a
single job so that you can see the entire
delivery process. Option v should never be
set in the configuration file; it is intended
for command line use only.
Vfallbackhost If specified, the fallbackhost acts like a
very low priority MX on every host. This is
intended to be used by sites with poor net-
work connectivity.
w If you are the "best" (that is, lowest
preference) MX for a given host, you should
normally detect this situation and treat that
condition specially, by forwarding the mail
to a UUCP feed, treating it as local, or
whatever. However, in some cases (such as
Internet firewalls) you may want to try to
connect directly to that host as though it
had no MX records at all. Setting this
option causes sendmail to try this. The
downside is that errors in your configuration
are likely to be diagnosed as "host unknown"
or "message timed out" instead of something
more meaningful. This option is disrecom-
mended.
xLA When the system load average exceeds LA, just
queue messages (i.e., don't try to send
them). Defaults to 8.
XLA When the system load average exceeds LA,
refuse incoming SMTP connections. Defaults
to 12.
yfact The indicated factor (fact) is added to the
priority (thus lowering the priority of the
job) for each recipient, i.e., this value
penalizes jobs with large numbers of reci-
pients. Defaults to 30000.
Y If set, deliver each job that is run from the
queue in a separate process. Use this option
if you are short of memory, since the default
tends to consume considerable amounts of
memory while the queue is being processed.
zfact The indicated factor (fact) or is multiplied
by the message class (determined by the Pre-
cedence: field in the user header and the P
lines in the configuration file) and sub-
tracted from the priority. Thus, messages
with a higher Priority: will be favored.
Defaults to 1800.
Zfact The fact or is added to the priority every
time a job is processed. Thus, each time a
job is processed, its priority will be
decreased by the indicated value. In most
environments this should be positive, since
hosts that are down are all too often down
for a long time. Defaults to 90000.
7 Strip input to seven bits for compatibility
with old systems. This shouldn't be neces-
sary.
All options can be specified on the command line using the
-o flag, but most will cause sendmail to relinquish its
setuid permissions. The options that will not cause this
are b, d, e, E, i, L, m, o, p, r, s, v, C, and 7. Also, M
(define macro) when defining the r or s macros is also con-
sidered "safe ."
If the first character of the user name is a vertical bar,
the rest of the user name is used as the name of a program
to pipe the mail to. It may be necessary to quote the name
of the user to keep sendmail from suppressing the blanks
from between arguments.
sendmail returns an exit status describing what it did. The
codes are defined in /usr/include/sysexits.h.
EX_OK Successful completion on all
addresses.
EX_NOUSER User name not recognized.
EX_UNAVAILABLE Catchall. Necessary resources were
not available.
EX_SYNTAX Syntax error in address.
EX_SOFTWARE Internal software error, including
bad arguments.
X_OSERR Temporary operating system error,
such as "cannot fork".
EX_NOHOST Host name not recognized.
EX_TEMPFAIL Message could not be sent immedi-
ately, but was queued.
If invoked as newaliases, sendmail rebuilds the alias data-
base. If invoked as mailq, sendmail prints the contents of
the mail queue.
FILES
dead.letter unmailable text
/etc/mail/sendmail.cf
defines environment for sendmail
/var/spool/mqueue/* temp files and queued mail
~/.forward list of recipients for forwarding mes-
sages
SEE ALSO
biff(1B), mail(1), mailx(1), newaliases(1), aliases(4)
hosts(4)
Su, Zaw-Sing, and Jon Postel, The Domain Naming Convention
for Internet User Applications, RFC 819, Network Information
Center, SRI International, Menlo Park, Calif., August 1982.
Postel, Jon, Simple Mail Transfer Protocol, RFC 821, Network
Information Center, SRI International, Menlo Park, Calif.,
August 1982.
Crocker, Dave, Standard for the Format of ARPA-Internet
TextMessages, RFC 822, Network Information Center, SRI
International, Menlo Park, Calif., August 1982.
