As we have already seen in Chapter 4, Lightweight
Directory Access Protocol (LDAP) is a very quick and powerful way to find specific
information about a particular user from a much larger group. For
example, you could use an LDAP server to look up a particular email address from a common
corporate directory by a user's last name. In this kind of
implementation, LDAP is largely separate from
Sendmail, with LDAP storing the hierarchical
user information and Sendmail only being
given the result of LDAP queries in pre-addressed email messages.
However, Sendmail supports a much greater
integration with LDAP, where it uses LDAP to replace separately
maintained files, such as aliases and
virtusertables, on different mail servers that
work together to support a medium- to enterprise-level
organization. In short, you can use LDAP to abstract the mail routing level from
Sendmail and its separate configuration files
to a powerful LDAP cluster that is being leveraged by many different
applications.
The current version of Sendmail contains support for LDAP. To extend
your Sendmail server using LDAP, first get an LDAP server, such as
OpenLDAP, running and properly configured. Then, you need to edit your
/etc/mail/sendmail.mc to include:
LDAPROUTE_DOMAIN('yourdomain.com')dnl
FEATURE('ldap_routing')dnl |
 | Note |
|---|
| | This is only for a very basic configuration of
Sendmail with LDAP. Your configuration should
differ greatly from this depending on your implementation of LDAP,
especially if you wish to configure several
Sendmail machines to use a common LDAP
server.
Consult /usr/share/doc/sendmail/README.cf for
detailed LDAP routing configuration instructions and examples.
|
Next, recreate your /etc/sendmail.cf file by
running m4 and restarting
Sendmail. See the section called Common Configuration Changes for instructions on doing this.
For more information on LDAP, see Chapter 4.
