Hello,

Is there any way to distribute the roles of a Mail server on Linux just like MS Exchange Server?

What I wanted here is, I need to have IMAP/POP server configured on different server , MTA i.e Postfix on other and Webmail on 3rd.

is it really possible

I'm sure this is possible. Why do you need this setup and what are you trying to achieve?

Even I am pretty sure this can be achieved. What i wanted to configure is Postfix MTA on one box acting as MailGateWay relays mail for exmaple.com to internal MTA which is again postfix acting as a smart host. Once mail is dropped here Postfix should deliver the mail to another Dovecot server sitting on a separate server from where Users can retrieve their mails.

INTERNET ------>MX {example.com is mail.example.com}---->[mail.example.com: Postfinx running]----->.relays to another MTA---->Delivery to Dovecot.

You do realize, don't you, that if you have any people who might want to use IMAP at work and webmail elsewhere that you'll have to have your message store mirrored on both the IMAP/POP3 server and the Webmail server. That seems like a lot of wasted disk space and synchronization errors.

What if someone replies to an email from their IMAP client at work, then they want to work from home over the weekend... the web client won't show that sent message (because it's stored on the IMAP/POP3 server). And if they clean out some spam and file some messages into folders via the web client, then what happens when they get back to work? How will you synchronize those deletions and filings?

I think you're better off supporting IMAP/POP3/webmail on one server, with one message store.