Author: Jeremy Harris Date: To: David Cannings CC: exim-users Subject: Re: [exim] Implementing a secondary MX
David Cannings wrote: > This works, the implementation passes on mail correctly for the right
> domains. However, there is potential for plenty of collateral bounces.
> For example, the primary MX receives a mail from the backup MX and
> decides it doesn't like it (spam, stricter ACLs, no-such-mailbox etc.)
> so rejects it. The backup is then going to attempt to send out a bounce
> to the originating host. The no-such-mailbox problem could be countered
> by having a list of valid users on the backup MX, that isn't hard to
> solve. However, I see no way to fix the first two.
A secondary needs access to all the same info as the primary, and needs
to make the same decisions.
