Migrating huge email server from exchange to Linux

[dud]

What is the best mail server to handle with certain security, and not too much resource consuming over 40.000 users.
I have already a Exchange Server doing this "almost" fine. I´m trying to move to Linux but I´m finding some resistance (from crappy mail administrators that does not want to work).

Thanks in advance.

[error27]

Here is probably the wrong place to be asking this...

Sendmail is obviously able to handle that kind of a load. I saw in another post that you have tried sendmail.

There are other email servers you could try. But sendmail would be the first thing that comes to my mind. The Sendmail.com guys would be happy to sell you their proprietary sendmail GUI configuration packages. This would probably make the other system admins happier.