While you can download the source code for
Sendmail and build your own copy, many users
prefer to install Sendmail via RPM from the
CD-ROM (at the time of the Red Hat Linux installation or at a later point).
The Sendmail application is placed in /usr/sbin.
Sendmail's lengthy and detailed configuration
file (sendmail.cf) is installed in
/etc. You should not edit the
sendmail.cf file directly unless you know exactly
what you are doing, due to the fact it is very lengthy and
complex. Instead, to make configuration changes to
Sendmail, edit the
/etc/mail/sendmail.cf file and use the included
m4 macro processor to create a new
/etc/sendmail.cf (after backing up the original
/etc/sendmail.cf, of course). More information on configuring
Sendmail can be found in the section called Common Configuration Changes.
Various Sendmail configuration files are installed in
/etc/mail including:
access — Specifies which systems can
use Sendmail for relaying email.
domaintable — Allows you to provide
domain name mapping.
local-host-names — The place where you
include all aliases for your machine.
mailertable — Specifies instructions that
override routing for particular domains.
virtusertable — Permits you to do a
domain-specific form of aliasing, allowing multiple virtual
domains to be hosted on one machine.
Several of the configuration files in /etc/mail,
such as access, domaintable,
mailertable and virtusertable,
must actually store their information in database files before
Sendmail can use any configuration
changes. To include any changes you make to these configuration in their
database files, you must run a command with the syntax makemap
hash /etc/mail/name <
/etc/mail/name where
name is the name of the configuration file to
convert.
For example, if you want all email addressed to any
domain.com account to be delivered to
<bob@otherdomain.com>, you need to add a line to the
virtusertable file:
@domain.com bob@otherdomain.com |
Then, to add this new information to the
virtusertable.db file, execute makemap
hash /etc/mail/virtusertable < /etc/mail/virtusertable as
root. This will create a new virtusertable.db that
contains the new configuration.
