We have a set of primary mail servers, let's call it A. We also have two
backup mail servers B and C (which should operate on the same MX
priority but a slightly different problem occurs even if they wouldn't).
Figure the case where a mail is to be delivered to a particular mail
server in the set A but that server is down so it is delivered to B
instead. B then tries to deliver to the primary server but it's still
down so it goes on in the MX priority and sends the mail to C insteads.
And here's where the loop begins I think, because C will then re-send it
to B won't it?
I haven't really seen this in action because our second backup mail
server isn't active yet. How do I configure the backup mail server to
only deliver mail to the end destination (which could be defined as the
highest MX priority (lowest MX value) for that domain).
Note that A isn't well-defined, it's a set of several primary mail
servers. Actually it's the set of every mail server that is defined as
the highest MX priority for every domain in relay_domains.
I'm sure there's a nice way to tackle this problem, I just don't know how.
Thanks,
Patrik
