Sendmail nullclient configuration on CentOS v5.2

Sendmail is the work of the devil.

Here, however, is how to set up a nullclient, which will enable all mail from a server to be forwarded to a central mail hub.

[root@server1 mail]# rpm -qa | grep sendmail
sendmail-cf-8.13.8-2
sendmail-8.13.8-2
[root@server1 mail]# cat /etc/mail/sendmail.mc
divert(-1)dnl
dnl #
dnl # This is the sendmail macro config file for m4. If you make changes to
dnl # /etc/mail/sendmail.mc, you will need to regenerate the
dnl # /etc/mail/sendmail.cf file by confirming that the sendmail-cf package is
dnl # installed and then performing a
dnl #
dnl # make -C /etc/mail
dnl #
include(`/usr/share/sendmail-cf/m4/cf.m4')dnl
VERSIONID(`Nullclient for Linux')dnl
OSTYPE(`linux')dnl
DOMAIN(`generic')dnl
FEATURE(`nullclient',`example.com')dnl
undefine(`ALIAS_FILE')dnl

[root@server1 mail]# cat /etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
192.168.0.1 server1.example.com server1

[root@server1 mail]# make -C /etc/mail
make: Entering directory `/etc/mail'
make: Leaving directory `/etc/mail'
[root@server1 mail]# service sendmail restart.
Shutting down sm-client: [ OK ]
Shutting down sendmail: [ OK ]
Starting sendmail: [ OK ]
Starting sm-client: [ OK ]
[root@server1 mail]#

Oviously, you could always add those lines into a file called something like null.mc and then create your sendmail.cf file with a command line like:

[root@server1 mail]# m4 null.mc > sendmail.cf


Just discovered that much of this is covered over at faqs.org.