Author: W B Hacker Date: To: exim users Subject: Re: [exim] using different ports for different mx preferences
Ian Eiloart wrote: >
> --On 19 February 2008 17:59:03 +0000 W B Hacker <wbh@???> wrote:
>
>> ELSE - don't publish it, as you are contributing to breaking
>> RFC-mandated behaviour for the many who *need* backup MX to function as
>> expected.
>
> If does when the same machine is listening. If you can't get through to one
> IP address on my host, you're welcome to try the other. You just won't find
> anything there. I don't see how two missing hosts are worse than one.
>
You are ignoring the parts of the world beyond your control.
There are typically a dozen or more hops between international MX'en.
'traceroute' a few of your correspondents and see.
If ANY ONE of those inks is out of service - even briefly - the
*possibility* exists that a sending MTA will try to fall back to your
published secondary (et al) MX. Uncommon, but it happens - see recent
fibre cable outages.
Not a spammer. Nothing amiss with your server. Nor theirs.
MTA can't read newspapers very well.
So they legitimately arrive on your published backup - and you drop them
on the floor.
Is that what your employer wants?
I've got strict server rules - but that method is not among them.
Better to not publish the backup.
