How to setup INCOMING ONLY mail server on Linux

Question

Hi,

Sorry if this is a very basic question (I couldn't find any tutorial on google so asking here).

I want to setup an INCOMING ONLY mail server on Linux. (I have some websites, for which I wish to avoid google apps or some other solution). There are some reasons why I want my own incoming server (like ease of scripting, etc).

Anyways, so I couldn't find any tutorial on this. (There must be some out of the box solution also?).

Further - how to ensure it is secure? I have heard spammers can attack a not-so-well secured mail server to send spam (thats with outgoing mail server - are there too many risks associated with even an INCOMING mail server)?

Thanks much,

JP

PS: I have average knowledge of linux administration but am totally a newbie with mail servers.