Comment Custom or Commercial suggestions (Score 1) 1216
You have two options. Create a custom solution or use a commercial one. I ended up having to create a custom solution for the 85k mailboxes I manage.
Having investigated scalable mail systems I would recommend at least taking a look at Mirapoint. They aren't perfect but they are professional and have a very nice solution, though it will cost you.
If you're going to do things yourself I'd suggest looking at some of the following:
Using the above you can setup front end mail exchangers doing various anti-spam and anti-virus work in a load balanced setup with dynamic banning of IPs based on logs of refused mail. They should make use of LDAP so you don't allow any mail in that is destined for a non existant user.
Then you can use this to balance multiple back end servers of virtually any description. You could even have multiple vendor solutions used for the backend servers. Of course you'll need to tie it all together with custom administration scripts, etc
Having investigated scalable mail systems I would recommend at least taking a look at Mirapoint. They aren't perfect but they are professional and have a very nice solution, though it will cost you.
If you're going to do things yourself I'd suggest looking at some of the following:
- RedHat Enterprise Linux 4
Has most of the following already installed and you'd want to subscribe to a version of RHN that let you rapidly roll out new servers or upgrades/security patches to existing servers - OpenLDAP
Can be used for authentication and directing mail and pop/imap or even webmail session to the appropriate backend mail stores. - Perdition
POP/IMAP proxy can use LDAP - Postfix
Again can use LDAP - Apache with PHP
I used this to proxy/redirect webmail logins - Webmin
It's cluster feature is actually quite handy and it's monitor scripts along with some Perl make for a quick and easy monitoring solution.
Using the above you can setup front end mail exchangers doing various anti-spam and anti-virus work in a load balanced setup with dynamic banning of IPs based on logs of refused mail. They should make use of LDAP so you don't allow any mail in that is destined for a non existant user.
Then you can use this to balance multiple back end servers of virtually any description. You could even have multiple vendor solutions used for the backend servers. Of course you'll need to tie it all together with custom administration scripts, etc
