postfix mail server setup for 8000 users using active directory [closed]

i wanna to setup postfix mail server instead of ms exchange server . we have around 8000 users , and we want to use active directory for users . how many servers do we need ? what kind of strategy we should choose ? how to use ad users in mail server ?

Solution 1:

it more depends on how many messages/sec will you have to handle rather than number of users. 8k users is not a lot and you can handle such load for typical home users without problems on any modern hardware.

remember that postfix is MTA - will handle nicely mail routing / sending, but it does not provide access to the local mail store - you'll need something like courier or dovecot for pop3/imap access.

so if you look for exchange replacement - it'll have two layers [ which can run on one machine.. ]:

1. mail routing - postfix: messages come here from the content filters; at this level decision is taken to which server mail should be delivered.
2. mail storage - postfix + courier or similar: messages get delivered here, end-users connect to those servers to check their inboxes.

and possibly 3rd group of machine for outgoing mails

at this scale you probably want to make all the levels redundant. at the beginnign you can start with running all of those on two virtualization servers with reasonably fast io subsystem and reasonable amounts of memory [ it all depends on usage pattern - but i would start with 32GB per box, 8x 15krpm disks ].

such approach should give you quite nice scalability if you might have more users in the future.

i suggest you do not let postfix query ldap continuously to check if given mail address is valid or not. instead - use batch job that will extract all valid mail address from active directory every few hours and populates local sql database that postfix will query.

this script can give you idea how to extract addreses from ad.

Solution 2:

Let me ask you this - why are you using MS Exchange?

If you doing more than just email with Exchange, postfix is not likely a good solution. You need to find a mail solution that is comparable to Exchange - something like "Zimbra":

http://www.zimbra.com/

Solution 3:

Postfix with fedora directory server easy install and config/manage http://studyhat.blogspot.com/2009/10/how-to-setup-fedora-directory-server.html