Originally Posted by
peterb
Fedora is a Linux distribution - one of many - but I guess if you are asking this, you have little Linux experience and the Postfix/dovecote route is one that you might not feel comfortable with...?
Strictly speaking, Linux referees to the core or kernel of the operating system, the bit that handles IO, time sharing, the low level suff. A distribution is the kernel and all the ancillary bits that make it into a fully fledged and useable system, file managers, the shell, and so one.