How to install and configure sendmail?

Ans :

1. Install :

#yum install sendmail*
#yum install m4*

2.
vi /etc/mail/sendmail.mc

Make commented like to accept all network :

----
dnl # DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
----

save this file.

3. Execute following command :

#m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf

4. Dont forget to add the following line to your /etc/hosts.allow file:

----
sendmail: ALL
----

5. Set DAEMON to yes in /etc/sysconfig/sendmail

----
DAEMON=yes
QUEUE=1h
----

5. Do following :

#chkconfig sendmain on
#service sendmail start

Testing :

1. Check whether port listens :

#netstat -tulpn | grep 25
#telnet localhost 25
#telnet IP 25

2. Above are fine then send a mail :

#echo test | mail -s test-subject -v


Note : sendmail configurations files are inside /etc/mail/. Log is inside /var/log/maillog.