[CALUG] help with dns reverse PTR record problem

[Jim Bauer]

For the SPF (special TXT) records you can configure, I believe the
PTR information needs to already exist.  If there is no PTR for your
address(es) at all, they would still need to be created (see below).  If 
there is one, but just doesn't point your your domain (i.e. point to 
something in you IPS's domain) then I think you can list that as an 
'additional PTR address' (3rd bullet in part 7 of SPF section at the web 
page you referenced).  Whether concast will accept that, I have no idea.

For PRT records, you'll likely need the assistance of your ISP.  i.e. 
whoever assigned you the IP address(es) in question.  They can either 
delegate (highly unlikely) a portion of the reverse namespace to you or 
(more likely) you tell them what you want it to point to and they take 
care of it.

Another option would be to relay your outgoing email through an email 
server at your ISP (if they provide such a service).  Although keep in 
mind that such a service may require your to do something like a pop or 
imap login from the same address before it'll accept mail over smtp (to 
prevent spamers from using their email server as spam relays).  I don't 
know if that would work well for business usage.



On 11/28/2010 09:08 PM, Duane Tucker wrote:
>
> Hi all,
>
> I'm looking for someone who would be willing to help me with a DNS
> problem. I'm willing to pay for your time.
>
> Background: I administer the network and servers for a small company. I
> have a linux server running postfix for outgoing smtp email. The domain
> is registered with godaddy and I use the godaddy DNS Manager tool for
> dns control.
>
> The problem is this: when someone inside the network attempts to email
> anyone at a comcast.net address,  Comcast rejects the emails with the
> following message:
>
> Nov 28 20:18:17 mailserver postfix/smtp[10207]: 4F0E36FD08:
> to=<teset at comcast.net>, relay=mx1b.comcast.net[76.96.62.116]:25,
> delay=19637, delays=19636/0.08/1/0, dsn=4.0.0, status=deferred (host
> mx1b.comcast.net[76.96.62.116] refused to talk to me: 554
> imta04.westchester.pa.mail.comcast.net comcast 69.85.36.83 Comcast
> requires that all mail servers must have a PTR record with a valid
> Reverse DNS entry. Currently your mail server does not fill that
> requirement. For more information, refer to:
> http://help.comcast.net/content/faq/PTR)
>
>
> Comcast is the ONLY domain in almost 2 years that we have this problem
> with. Luckily, we almost never need to email anyone with a Comcast
> address. This problem has reared its ugly head only 3 or 4 times. It
> drives me nuts, however, that I can't figure out how to fix the problem.
> This weekend I even stumbled through setting up my own DNS server, using
> bind, but then couldn't figure out how to implement it. The reason for
> my confusion here is that in the godaddy dns manager, it requires me to
> enter a FQDN for the name servers, not an IP address. Well, if the
> purpose of the DNS server is to resolve names, and the DNS server is
> running within the same domain that your trying to resolve, how in the
> world would it ever get there for resolution?!?
>
> Now you would think that the answer would be easy. Since I'm managing
> dns entries with the godaddy dns manager, why not just put a reverse PTR
> record there? But no, that's just too easy. Godaddy doesn't allow you to
> enter PTR records. They do have some perverted way to enter TXT records
> with a PTR embedded, but I can't figure that out either. When I called
> godaddy tech support, they politely informed me that since I don't use
> their hosts, they can't provide support for the dns entries. Sigh. By
> the way, here is a link to a godaddy support page discussing the
> TXT/PTR/SPF "thing".
>
> http://community.godaddy.com/help/article/680
>
> So if anyone reading this thinks they can help, please do let me know.
> I'm tired of spending weekends now and then chasing my tail. I know just
> enough about all this to be dangerous. The answer could be just one
> small step away and I simply can't see it.
>
> Many thanks,
> Duane Tucker
>
>
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