I’ve come across some really curly mail challenges in my time. The customer wants mail delivered to a user, specified not in the To: field, but in the subject line you say? Oh, you want to deliver mail to users authenticated from Active Directory, but there are 3 domains and users might exist in any (and more than) one?

Both of these are problems I’ve encountered in real life, amongst many others, and every time I’m able to lean on Exim, knowing there will be a way.

I am in awe of the power and flexibility of this mailer. There is literally nothing it can’t do. It can do Lookups against almost anything you can think of and can integrate easily with content filtering for antivirus and antispam. You can even extend it with Perl, if you want to get funky.

And what’s even better is that the configuration is so easy to use and understand. Everything is in there, not just changes to defaults as is the case with most software. It’s more like a delivery instruction manual than a configuration. This might scare people off initially, it’s a big file, but the beauty of it is you can see exactly what’s going to happen at every stage of a messages delivery cycle. And change it if you want to.

It helps of course that Exim on Debian is extremely well packaged. The configs are well commented and easy to extend. However Exim can be just as easy and powerful on other platforms, with a little extra effort.

If you’re still struglling away with Postfix or, heaven forbid, Sendmail, join the 21st century and try out Exim. You won’t regret it.

Luke.