Can MS Exchange play nice with the mailing lists?

[Chuck Swiger]

On Dec 3, 2010, at 11:29 AM, John D McDonnell wrote:
> Received: from exchange.pcam.local (unknown [68.234.51.1])  <-- Note 1
>     by godfather.dreamhost.com (Postfix) with ESMTP id 11CE91B006A
>     for <gorgarath at gorgarath.com>; Fri, 3 Dec 2010 11:14:20 -0800 (PST)
> Received: from exchange.pcam.local ([10.10.0.13]) by exchange.pcam.local
> <-- Note 2
>     ([10.10.0.13]) with mapi; Fri, 3 Dec 2010 14:14:19 -0500
[ ... ]
> Note 1: Not sure why our external IP address is showing up with the name
> exchange.pcam.local instead of mail.pcam.local, but I'm pretty sure
> that's what I need to fix to be able to send to the FreeBSD mailing
> list, and anyone else who rejects similar mails.

Yes.  If your domain is really pcam.org, tell this box it is exchange.pcam.org and get reverse DNS setup for IP 68.234.51.1. Evidently, you have a mail.pcap.org, presumably your incoming MX host, at IP 68.234.51.13.

> Note 2: Not sure if this is an issue or not since it is an internal IP
> address and not the last hop before heading out into the wild.

It's normal for MTAs to list all hostname/IP combinations in Received: headers, to help avoid mailing loops.

Some people view this with a concern to security and disclosing internal information, but in practice any hacker who gains even minimal access can figure out your internal network info anyway, so it's not a big help.

> Note 3: I'm almost certain exchange.pcam.local isn't an issue here since
> I think Message-ID is a fairly arbitrary header in actual mail delivery

This won't matter in practice mostly, but it preferable to include a valid domain so that the Message-IDs are truly unique.

> Am I correct in my assumptions about the 3 instances of the .local
> domain? Is there anything else that looks wrong that I'll also need to
> take a look at? I'm not sure where in Exchange to change these settings,
> but I'll do some Googling and see what I can find. Preferably I'd like
> for it to refer to itself as mail.pcam.org on the inside and outside as
> we currently get a certificate error in Outlook on the inside due to it
> not matching mail.pcam.org.

It looks like you have a different box receiving emails...?

Regards,
-- 
-Chuck