Reverse DNS question

General Discussion
1

I’m sure this has popped up before, but I’ve still to get my head around it :slight_smile:

I have a server that serves both DNS, Web and Mail.

There is a separate IP address for 2 DNS servers and the web/mail.

Web/Mail : 12.34.56.78
DNS servers: 12.34.56.79 and 12.34.56.80

I have set up with my dedicated server hosting company a reverse IP of 78.56.34.12.in-addr.arpa domain name pointer server_host_name.mydomain.eu.

When I send an email out, the headers show:

Delivered-To: paul.pixel.co.uk@server_host_name.mydomain.eu
Received: from [192.168.1.5] (82-46-6-144.cable.ubr04.aztw.blueyonder.co.uk [82.46.6.144])
by server_host_name.mydomain.eu (Postfix) with ESMTP id 90DC37700AD
for paul@pixel.co.uk; Tue, 8 Dec 2009 21:59:41 +0000 (GMT)

and:

[~]$ host 12.34.56.78
78.56.34.12.in-addr.arpa domain name pointer server_host_name.mydomain.eu.

but I’m still getting this with one email address.:
550 Bad rDNS (in reply to MAIL FROM command)

Hotmail, GMail, Yahoo all work fine, but this one address (which goes via tidymail.co.uk) keeps rejecting my mail.

Anyone have some idea of what is incorrect here?

Thanks,

Paul

2

Yeah, it looks like your reverse DNS is good.

Perhaps the host having trouble had cached an old result? It could take a day or two before it clears out in some cases…

-Eric

3

Hi Eric,

Thanks for the reply - I’ll leave it a while longer.

Cheers,

Paul

4

doh!

I had the A record for server_host_name.mydomain.eu set it 12.34.56.79 instead of 12.34.56.78, so dig server_host_name.mydomain.eu was returning a different IP address, and so rDNS was wrong.

Paul