Author: Marc Sherman Date: To: exim-users Subject: Re: [exim] bouncing message, improper configuration of server.
Leonardo Boselli wrote: > I (or better my server) does not bounce around: just has a rule that if
> the two main servers (that offer pop3 and imap service to users,
> an that act as smarthosts for local users) cannot
> send directly within 5 minutes, to save CPU cycles, they pass
> the message to one of the backup servers (the ones with higher mx) that in
> turn tries next retries, using if failing one with a 4xx message (or
> being unable to connect), a different routing and of course a different
> ip. So in the worst case a message could be sent with 5 different IP from
> three different networks. But these are always from at most two servers !
That sounds like a server architecture specifically designed to
introduce delays in the face of common greylisting techniques that are
currently deployed. I don't like greylisting either, but it's a reality
on today's internet, and you should probably configure these servers to
hang on to mail for a few more retry cycles before passing it off to the
next ip in the pool.
