Re: [exim] Telling a secondary MX about valid addresses on t…

On Sat, Feb 26, 2011 at 13:32, Graeme Fowler <graeme@???> wrote:
> While that's perfectly valid, there are any number of reasons why a
> given source address would be able to connect to your secondary MX but
> not the primary. Almost none of those reasons are under your control,
> nor that of the source. If you're running a high-volume system (in terms
> of rate, or end users) then this will turn round and bite at some point.

Speaking as a co-admin of a medium-sized hosting company, I can attest
to the following:

1) Running a secondary MX with a lower (higher numbered) priority
means that MX will be bogged down with spam, spam, spam, spam, spam,
spam, spam, spam-sausages, and spam.
2) This bites. Hard.
3) Legitimate messages that are attempted delivered through said
secondary MX will be lost in the noise, and unduly delayed.

Our conclusion, several years ago, was therefore to keep all MXes at
the same priority.

There is no spoo^Wsecondary MX.

There are, however, a bunch of equally configured MXes, using the same
user/alias/domain databases, the same anti-spam and -virus
configurations, etc.

If I may be so unhumble: kill the secondary MX, or keep both its DNS
priority number and configuration the same as the "primary" MX - make
them both "primaries".
--
Jan