postfix/mail: server blacklisted -- what have I done wrong?

Derek Broughton news at
Fri Mar 24 20:32:21 UTC 2006

Matt Price wrote:

>> IIf they're really blacklisting servers for sending mail from FQDNs that
>> aren't MXes they should be shot.  There's no reason a _sending_ mail
>> address should be a valid MX.  There's also no reason that it should have
>> 'proper' reverse DNS.  My _proper_ domain,, is on a
>> hosting
>> service.  A reverse lookup on the IP is always going to show
>>  There's nothing wrong with that, either in
>> practice or in the various mail RFCs.
> glad to hear that's ok, the stringent requirement proposed here &
> elsewhere seemed a little strong.  In this particular case the error was
> the much more egregious localhost.localdomain one described above.
I didn't really mean to say it's "ok".  Many of the "blackhole" services are
ridiculously stringent.  They shouldn't be blacklisting someone just
because their IP doesn't reverse-DNS to their stated domain, but it
happens.  They may be wrong, but it'll be your problem :-(  As for sending
mail from an address that isn't an MX, I hadn't heard of that one - but it
makes no sense.

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