Exim: Different mail retry times depending upon response from remote host...

[Joe Emenaker <joe@emenaker.com>]

You don't have to be a rocket scientist to realize that the following 
remote mailer messages give varying degrees of optimism regarding future 
delivery:

   550 Requested action not taken: mailbox unavailable
   452 Mailbox full
   452 Insufficient disk space; try again later
   421 Too many concurrent SMTP connections; please try again later.

With the first, you're pretty sure that the problem is *not* going to be 
corrected in the next few days. Meanwhile, the others give you some hope 
in waiting.

Unfortunately, I haven't seen anything in Exim that lets you customize 
it's retry behavior based upon this. It does offer an "error" field in 
the retry section, but it's only for some silly hard-coded failure types.

So, I wrote a little script that goes through all of the msglog files 
and finds good candidates to toss (ie, "No such user", "Account 
Terminated", etc.). With just a day's worth of tweaking the script, I've 
managed to get the pending queue down to about 1/3 of what it was.

But I figured I'd ask... does anybody already have a script for doing 
this (or maybe a better way altogether, since this script has to be 
explicitly run periodically)?

- Joe