[clue-tech] weird dns problem

[David Anselmi]

Charles Oriez wrote:
> At 07:44 AM 1/12/2005, you wrote:
> 
>> Hi Charles,
>>
>> On Wed, 12 Jan 2005 07:29:36 -0700, Charles Oriez <coriez at oriez.org> 
>> wrote:
>> > I'm running into a weird problem that I hope is the way the ISP 
>> > managing dns has configured dns.

I thought it might be your mail server.  Or perhaps your DNS zone(s). 
But the plot thickens...

(Your dig output looks correct though it seems irrelevant since missouri 
isn't in the headers).

Let's look at the headers (the one to ohio is first, to rmc second, as 
you pasted them)...

Both say:

 > To: "'Charles Oriez'" <coriez at oriez.org>
 > Cc: <oriez at rmc.sierraclub.org>, <oriez at ohio.sierraclub.org>

and all below that is uninteresting.  Both messages took the same path 
through Comcast and then hit Sierra Club:

 > Received: from sccrmhc11.comcast.net ([204.127.202.55])
 >      by grassroots.sierraclub.org (8.12.8/8.12.8) with ESMTP id
 > j0C4U3gZ008754
 >      for <oriez at ohio.sierraclub.org>; Tue, 11 Jan 2005 21:30:03 -0700

 > Received: from sccrmhc11.comcast.net ([204.127.202.55])
 >      by rmc.sierraclub.org (8.12.8/8.12.8) with ESMTP id
 > j0C4P7Ye002576
 >      for <oriez at rmc.sierraclub.org>; Tue, 11 Jan 2005 21:25:07 -0700

So it looks like the MX for ohio is grassroots but the MX for rmc is 
rmc.  The next hop (geb) shows:

 > Received: from grassroots.sierraclub.org (grassroots.sierraclub.org
 > [207.174.21.172])
 >         by geb.den.nilenet.net (Postfix) with ESMTP id DA3AC1148E
 >         for <coriez at oriez.org>; Tue, 11 Jan 2005 22:27:05 -0700 (MST)

 > Received: from rmc.sierraclub.org (rmc.sierraclub.org [207.174.21.6])
 >         by geb.den.nilenet.net (Postfix) with ESMTP id 8ED6E11467
 >         for <coriez at oriez.org>; Tue, 11 Jan 2005 21:26:54 -0700 (MST)

Since the grassroots and rmc IPs are different it is likely that they 
are different machines.  I'd bet that the sending client sends one copy 
and Comcast splits it into two (because there are different destinations 
for ohio and rmc).  I doubt that Comcast mangles the From header.

Probably grassroots and rmc are configured slightly differently.  One 
mangles the From header (or the Return-Path header causing subsequent 
mangling of the From header, perhaps) and the other doesn't.

DNS may still have a role in this.  Maybe the sendmails behave 
differently because one is on rmc and the other isn't on ohio, or 
because of the MXs for the various machines.

Seems odd though to suspect DNS for wierd mail headers.

Dave