On 03/13/2013 07:03 PM, Austin Einter wrote: > Dear All > I have some basic doubts. > > 1. Do I need to run postfix like /etc/init.d/postfix restart > 2. What I found it , it is starting.., but when I check immediately ps -ef > | grep postfix, I do not see any postfix process running. In Centos we still have the service command, and it works well with services like postfix. So you start, restart, and stop with: service postfix start/stop/restart/status Note that at some point, probably Centos 7, 'service' is going away. Oh, and: chkconfig --list|grep postfix It should be on for all run levels if not: chkconfig postfix on > 3. Is there any system config file, where I need to mention system need to > run postfix not sendmail.... Did you install sendmail? grep sendmail /root/install.log service sendmail status chkconfig --list|grep sendmail > 4. If postfix is not running, how am I able to send mails out.... check to see what is running. > 5. I read some "make sure port 25 does not relay mails", can somebody > explain more in this regard and how do I stop port 25 relaying mails... Read to Postfix docs on this first then ask questions. Do a google search. This is something you need to know about. the campworld howto sets you up safe. If you got all of his stuff done.