Configuration Sendmail e-mail server

Note: use OpenSSL to generate your CSR, an example of OpenSSL for Apache can be found here.

After you receive your certificate file(s), store them here:

=> /etc/mail/ssl/sendmail.pem 
=> /etc/mail/ssl/ca-bundle.crt

Open sendmail configuration file /etc/mail/sendmail.mc using text editor such as vi:

# vi /etc/mail/sendmail.mc

Now append/modify following directives:

define(`confCACERT_PATH',`/etc/mail/ssl/certs')
define(`confCACERT',`/etc/mail/ssl/ca-bundle.crt')
define(`confSERVER_CERT',`/etc/mail/ssl/sendmail.pem')
define(`confSERVER_KEY',`/etc/mail/ssl/sendmail.pem')

And make sure port is set to smtps (secure smtp i.e. port 465):

DAEMON_OPTIONS(`Port=smtps, Name=TLSMTA, M=s')dnl

Restart sendmail and secure pop3s/imaps

Type the following commands to restart sendmail and related services:

# /etc/init.d/sendmail restart
# chkconfig pop3s on
# chkconfig imaps on
# /etc/init.d/xinetd restart

pop3s and imaps will start from xinetd