enterprise mail server in centos 6 or ubuntu 10.04
I need to configure an enterprise class secured e-mail server by using postfix (I don't want to use zimbra, I just want to get out of zimbra) in Centos 6 or Ubuntu 10.04 server. I need the following features in my mail server.
POP3 and IMAP access for users, mail forwarding, SMTP authentication for all out going mails, able to set quota for individual user mailbox, able to define e-mail attachment size for individual user, user themselves can be able to set automatic vacation response, Group e-mail, able to block certain kind of attachments in the e-mails, Squirrel Mail or roundcube as the web client. I have planned to configure licensed version of kaspersky antispam and antivirus for security.
Also I need to configure jabber chat server in the same machine and all the user has to login to their chat client using their e-mail ID and their password which i was created in the mail server, in simple words common authentication for both e-mail and chat for a user.
Please guide me how to achieve this,