sendmail, 4th Edition

Configuration Commands

The sendmail.cf configuration file is line-oriented. A configuration command, composed of a single letter, begins each line:

V10/Berkeley                       ← good
V10/Berkeley                       ← bad, does not begin a line
V10/Berkeley Fw/etc/mail/mxhosts   ← bad, two commands on one line
Fw/etc/mail/mxhosts                ← good

Each configuration command is followed by parameters that are specific to it. For example, the V command is followed by an ASCII representation of an integer value, a slash, and a vendor name. Whereas the F command is followed by a letter (a w in the example), then the full pathname of a file. The complete list of configuration commands^[21] is shown in Table 1-4.

Table 1-4. The sendmail.cf file’s configuration commands

Command	Description
C	Define a class macro.
D	Define a macro.
E	Define an environment variable (beginning with V8.7).
F	Define a class macro from a file, pipe, or database map.
H	Define a header.
K	Declare a keyed database (beginning with V8.1).
L	Include extended load average support (contributed software, not covered).
M	Define a mail delivery agent.
O	Define an option.
P	Define delivery priorities.
Q	Define a queue (beginning with V8.12).
R	Define a rewriting rule.
S	Declare a rule-set start.
T	Declare trusted users (ignored in V8.1, restored in V8.7).
V	Define configuration file version (beginning with V8.1).
X	Define a mail filter (beginning with V8.12).

Some commands, such as V, should appear only once in your sendmail.cf file. Others, ...