SMTP server for centOS, other than Postfix? [closed]

Solution 1:

sendmail! It's your friend, assuming you like your friends terse and hostile.

I exaggerate. I'm an old-time sysadmin and have grown up with sendmail, and I love it, though I concede it's not as friendly as some modern MTAs. It's wicked powerful, though, and will generally not let you down if you go to the trouble of configuring it. Also, many addons (greylisting, SPF checking, spamassassin integration) integrate well with it through the milter system, whereas some other MTAs either have the functionality built into the core, or you can't have it at all.

yum install sendmail sendmail-cf

will get you the binaries and the configuration tools. http://www.sendmail.org/doc/sendmail-current/cf/README tells about the actual configuration, but the essence is: you write a short configuration configuration file (sic, sendmail.mc), which is run through the m4 language to produce the actual configuration file (sendmail.cf). Unless you like pain, you never edit the .cf file directly, you always edit the .mc file and use m4 to regenerate the .cf.