[Ubuntu-PH] mailserver recommendations

[jan gestre]

guys,

i need your input on these, our company wants to set up a mailserver
in which users will be able to access their mail via web, the MTA i
have in mind is postfix, can you guys recommend the software i will
use in conjunction with postfix to set up a virus and spam free
mailserver with pop/imap access. the mailserver will be a member of a
windows dominated domain and will run thru a proxy. TIA.

jan