I want to set up a mail server with as much smaller memory footprint as possible on a Centos 5 very low end machine.
Bare minimum features is enough. :)
But what are my options? I can't seem to find anything like that. Or perhaps I can stripdown one of the well know packages?
Thank you.
For just SMTP I would say Postfix or Qmail. Those are quite lightweight to begin with and can be tunes easily. Postfix's modular nature allows you to disable any unused features and their processes. You can also tune Postfix to get the most out of limited resources.
If you need to add POP/IMAP then I think Dovecot is a good choice since it's uses few resources by default. A little more tuning can be done.
I run sendmail and dovecot on a very old CentOS 5 machine. Granted I don't use it for hundreds of people, but it works well enough.
My first choice would be postfix - it's compact, efficient, reliable and easy to manage. Sendmail certainly doe well in terms of reliability, and it can comfortably process huge volumes of emails but its a pig to configure and IMHO doesn't scale down as well as it scales up. I've not looked at qmail nor exim for some time, but previously did some research and found them to be not nearly as good in terms of reliability.
HTH
C.