[thelist] mail server problems

Anthony Baratta anthony at baratta.com
Wed Aug 1 16:54:17 CDT 2007

Who ever is your ISP needs to set that up. They are normally in charge of the DNS that would give your IP address a host name. So they can set it up.

Here is more detail on the issue for you to give them:

The  reverse DNS entry for an IP is found by reversing the IP, adding it to "in-addr.arpa", and looking up the PTR record.
So, the reverse DNS entry for is found by looking up the PTR record for
All DNS requests start by asking the root servers, and they let us know what to do next.
See How Reverse DNS Lookups Work for more information.

How I am searching:
Asking e.root-servers.net for PTR record:  
       e.root-servers.net says to go to figwort.arin.net. (zone: 208.in-addr.arpa.)
Asking figwort.arin.net. for PTR record:  
       figwort.arin.net [] says to go to NS2.SOFTLAYER.COM. (zone: 58.101.208.in-addr.arpa.)
Asking NS2.SOFTLAYER.COM. for PTR record:  Reports [from]

Answer: PTR record: [TTL 86400s] [A=None] *ERROR* There is no A record for (may be negatively cached).

-----Original message-----
From: Brian Cummiskey brian at hondaswap.com
Date: Wed, 01 Aug 2007 13:11:05 -0700
To: "thelist at lists.evolt.org" thelist at lists.evolt.org
Subject: [thelist] mail server problems

> Hi guys,
> this might be a little offtopic, but i'm having some issues with my mail 
> on my webserver....
> i can't seem to send to addresses that require reverse lookups, namely 
> craigslist.
> host mxi1s.craigslist.org []: 554 <unknown[]>:
>     Client host rejected: rDNS/DNS validation failed. Please setup matching DNS and rDNS records:
> how do i set up dns and matching rdns records?
> i have cpanel and am on RH enterprise if it matters.

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