Hello,

I am mostly happy using Postfix. Its address rewriting capabilities are not as complete as those of Sendmail, but then Sendmail can't query an SQL database. Also, everything I've needed with do with an MTA turned out to be not only do-able with Postfix but also do-able much more easily and intuitively than with Sendmail.

I am mostly happy with it, but not completely happy. One thing that bothers me, and which others have already observed, is Wietse's attitude that some things should be a certain way, and that's the way it's going to be -- 'if you want it to behave differently, then write your own MTA.' Another is that the documentation, which, although good overall, isn't complete: one still has to read and post questions in the Postfix newgroups if one is serious about using Postfix. For example, the documentation will not tell you that a recipient address of <postmaster> will be accepted by default, even though some of the smtpd_*_restrictions are violated.

Exim is another popular alternative to Sendmail. From what I've read, it has a sane configuration file, and hence it is easier to use than Sendmail; but its performance isn't as good as Postfix's when it comes to flushing a large queue (which probably does not matter much in my enviroment). I am interested in hearing from those who have used both Postfix and Exim about the pros and cons of each. Is there anything which is more easily implemented in Exim than in Postfix (I have heard that Exim is more capable, but I haven't heard any specifics)? Is there anything which Postfix can do easily, but which is nontrivial in Exim? I like the concept of address classes of Postfix -- local, relay, virtual_mailbox,
etc. -- which make it very easy to specify which recipient addresses are valid for each class, along with the default delivery agent for the class. Does Exim have something similar? How do the documentation of the two compare? With the many, independent daemons of Postfix, the flow, sequence, and big picture is difficult to grok. Does the monolithic architecture of Exim make it easier to understand?

I've been running a postfix server for the last 3 years, and I've been really happy with it. If you think Wietse is opinionated, you should take a look at D.J.B. and qmail... it is what it is and if you want anything else you have to patch it..

Sorry I can't give you a comparison of exim to postfix as you requested though.. I've been extremely happy with postfix stability and performance, I haven't bothered to look at Exim even though it is the default mailserver in Debian which is my prefered distro..

Thanks for the comment. I also have been running Postfix for a number of years. NetBSD just announced that it's going to ditch Sendmail (in favor of Postfix, I think).