[TriLUG] sendmail vs. postfix - was Re: stupid sendmail question?

[Jason Tower]

> On the flip side, that 5% of things that Sendmail can do that Postfix
> can't, can be *really* nice.  Postfix does not have Sendmail's milter
> interface.  What the Milter interface allows you to do, is reject
> messages on the fly, as part of the SMTP session, for what ever
> reason you see fit.  Spam, Viruses, Malformed messages, what ever --
> you don't generate NDRs, you just say "No Thanks" and stop talking to
> the sending host.  Postfix does not have an elegant way to implement
> this.  You can sit a spam/virus daemon in front of your MTA that's
> capable of doing it, but that's not an elegant solution.  For most
> low volume sites this isn't really a problem, but for larger volume
> sites it can be a real headache as queue sizes grow unmanageable.

in my experience postfix's more modular nature means that additional 
functionality can be added on relatively easily.  for example, postfix 
2.1 includes the "verify" feature which enables it to see if a message 
is deliverable *before* the smtp data is accepted - if not, it returns 
a 550 to the sender.  no bounces, nothing gets queued.  this is 
incredibly useful when using postfix as a gateway, often in conjunction 
with amavis/spamassassin/clamav/etc.

jason