SMM:08-10
Sendmail Installation and Operation Guide
1.3.1. /usr/sbin/sendmail
The binary for sendmail is located in /usr/sbin
1
. It should be set-group-ID smmsp as
described in sendmail/SECURITY. For security reasons, /, /usr, and /usr/sbin should be owned
by root, mode 0755
2
.
1.3.2. /etc/mail/sendmail.cf
This is the main configuration file for sendmail
3
. This is one of the two non-library file
names compiled into sendmail
4
, the other is /etc/mail/submit.cf.
The configuration file is normally created using the distribution files described above. If
you have a particularly unusual system configuration you may need to create a special version.
The format of this file is detailed in later sections of this document.
1.3.3. /etc/mail/submit.cf
This is the configuration file for sendmail when it is used for initial mail submission, in
which case it is also called ``Mail Submission Program'' (MSP) in contrast to ``Mail Transfer
Agent'' (MTA). Starting with version 8.12, sendmail uses one of two different configuration
files based on its operation mode (or the new -A option). For initial mail submission, i.e., if one
of the options -bm (default), -bs, or -t is specified, submit.cf is used (if available), for other
operations sendmail.cf is used. Details can be found in sendmail/SECURITY. submit.cf is
shipped with sendmail (in cf/cf/) and is installed by default. If changes to the configuration need
to be made, start with cf/cf/submit.mc and follow the instruction in cf/README.
1.3.4. /usr/bin/newaliases
The newaliases command should just be a link to sendmail:
rm -f /usr/bin/newaliases
ln -s /usr/sbin/sendmail /usr/bin/newaliases
This can be installed in whatever search path you prefer for your system.
1.3.5. /usr/bin/hoststat
The hoststat command should just be a link to sendmail, in a fashion similar to
newaliases. This command lists the status of the last mail transaction with all remote hosts.
The -v flag will prevent the status display from being truncated. It functions only when the
HostStatusDirectory
option is set.
1.3.6. /usr/bin/purgestat
This command is also a link to sendmail. It flushes expired (Timeout.hoststatus) informa-
tion that is stored in the HostStatusDirectory tree.
1
This is usually /usr/sbin on 4.4BSD and newer systems; many systems install it in /usr/lib. I understand it is in /usr/ucblib on
System V Release 4.
2
Some vendors ship them owned by bin; this creates a security hole that is not actually related to sendmail. Other important di-
rectories that should have restrictive ownerships and permissions are /bin, /usr/bin, /etc, /etc/mail, /usr/etc, /lib, and /usr/lib.
3
Actually, the pathname varies depending on the operating system; /etc/mail is the preferred directory. Some older systems in-
stall it in /usr/lib/sendmail.cf, and I've also seen it in /usr/ucblib. If you want to move this file, add -D_PATH_SENDMAIL-
CF=\"/file/name\" to the flags passed to the C compiler. Moving this file is not recommended: other programs and scripts know of this
location.
4
The system libraries can reference other files; in particular, system library subroutines that sendmail calls probably reference
/etc/passwd and /etc/resolv.conf.