AT&T refuses to provide PTR records?

Mark Foster blakjak at blakjak.net
Wed Oct 18 09:21:25 UTC 2006



On Tue, 17 Oct 2006, Jack Bates wrote:

>
> Mike Walter wrote:
>> We have a customer that has AT&T and they reassigned the IP space to our
>> name servers to allow us to do reverse DNS for them.
>> 
>
> We had a similar situation. AT&T states that they will only handle rDNS using 
> domains that they control. They will happily CNAME the IPs appropriately or 
> reassign the IP space, depending on block size and request.
>
> The issue we ran into was that we couldn't get them to *unassign* a CNAME for 
> an IP block so that it would fail immediately, and so servers (web,ftp, etc) 
> which requested rDNS for the connection information would time out 
> connections waiting for the non-existent nameservers. We weren't really 
> interested in handling rDNS for the IP given that it wasn't handling mail, 
> web, or have any A records pointing to it. It is the easiest way to get it 
> done, though.
>

Surely if you have _a_ matching forward and reverse DNS pair, that'd get 
you started?

My experience in this game was that you could create mail.xyz.com and 
point it to their IP as an A record, and point MX at this - no problems.
So long as the host had a valid and matching forward/reverse DNS entry 
there was no grief.

The issue was where there was no matching A/PTR set, this would increase 
the likelyhood of a spam host or something... right?

Or is it now a case of A/PTR must match the MX?

Mark.



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