> On Monday, November 18, 2013 7:57 AM, Kris Deugau <kdeu...@vianet.ca> wrote:
> > E.B. wrote:
>
>> Hello,
>>
>> My understanding was clients for whom you see this in the logs:
>>
>> connect from unknown[1.2.3.4]
>>
>> Do not have a PTR/rDNS set up for themselves.
>
> For Postfix to include the rDNS in the log and Received: header, the PTR
> name must then resolve back to that same IP as well.
>
> Sometimes there will be a PTR record, but no matching A record.
>
> Also keep in mind that if there is a temporary glitch in DNS resolution,
> either the PTR or A lookup might fail when the message first passes
> through, but looks fine later on when you check by hand.
Thanks. So my understanding is correct that Postfix gets the hostnames you see
in the logs from PTR records? And that "connect from unknown[1.2.3.4]" is
caused by a missing PTR (or DNS issue)?
You are saying that additionally, if the A record for the domain doesn't match
the client IP, the PTR will be ignored and thus you'll still get "unknown"?
That would all make sense.
In my case, my PTR and A records look good, and online tools (mxtoolbox, etc)
seem to verify this. The "dig" command comes back looking good as well. Yet, I
keep getting "connect from unknown" (from my server, but others, like email
coming from gmail work correctly). I will have to assume that there is some
kind of glitch in the DNS lookups Postfix is doing for my domain/host.
Thanks again.
