The sendmail configuration file (usually called
sendmail.cf, but for MSP submission, called
submit.cf) provides all the central information
that controls the sendmail
program's behavior. Among the key pieces of
information provided are the following:
The location of all the other files that
sendmail needs to access and the location of all
the directories in which sendmail needs to
create and remove files.
The definitions that sendmail uses in rewriting
addresses. Some of those definitions can come from files, which are
The mail header lines that sendmail should
modify, pass through, and/or augment.
The rules and sets of rules that sendmail uses
for transforming mail addresses (and aliases for those addresses)
into usable information, such as which delivery agent to use and the
correct form of the address to use with that delivery agent.
The external programs though which sendmail
should filter messages to detect and eliminate spam and viruses.
The location of the sendmail.cf (and
submit.cf) file is compiled into
sendmail. Beginning with V8.10,
sendmail expects to find its configuration file
in the /etc/mail directory. Prior to V8.10, the
configuration file was usually found in either the
/etc, the /usr/lib, or the
/etc/mail directory. (See _PATH... for a description of how to change the
default.) We recommend that the standard
/etc/mail location be used unless you have a
compelling reason to do otherwise. A nonstandard location can, for
example, make operating system upgrades difficult.
The configuration file is read and parsed by
sendmail every time it starts up. Because
sendmail is run every time electronic mail is
sent, its configuration file is designed to be easy for
sendmail to parse rather than easy for humans to