Thank you all for this valuable information and advice. I appreciate it. I
have been thinking a lot about this over the past few days. Currently we
have Backup MX servers (Windows-based) in place for a few of our
Windows-based mail servers and they have been working quite well. We really
don't have much of a problem with spam because Message Sniffer,
SpamAssassin for Windows, and a few other AS/AV programs we are using are
doing a really great job in keeping spam to a minimum.
I was chatting with one of my colleagues about the advice that you guys and
the Postfix list members provided. A saw a few times during those posts
that MX backup servers are probably not a good idea in general and the
reasons all seem to be pointing to the spammer problem. Since this is the
case, I brought up the subject of anti-spam gateways since we use those as
well in our environment. In the event of a primary server outage, our
gateways spool the mail until the primary server becomes available again,
however, if the gateway had an outage or failure, we would be in the same
boat. The mail would be rejected/bounced. I'm aware that most commercial
gateways use a round-robin so that they can essentially be "always up", but
what about the smaller clients who run their own mail server from their
offices and cannot afford a good gateway solution? I think folks in that
situation would benefit from a backup MX. That is why we implement them for
a lot of our smaller clients. So far, so good. :)
With that being said, besides the issues with spammers which we feel we
have a good handle on, are there any other reasons why a backup MX is still
not a good idea?
Thanks again!
On Wed, Apr 8, 2020 at 6:48 AM Gedalya via Exim-users <exim-users@???>
wrote:
> On 4/8/20 4:33 AM, Andrew C Aitchison via Exim-users wrote:
> >
> > Exim does recipient callouts and cutthrough delivery.
> > Are either of these useful for an MX backup ?
>
> Callout caching can be potentially useful when the primary is down. Not a
> complete solution of course.
>
>
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