Emails bouncing due to relay.ptn-ipout01.plus.net being blacklisted

[#1]

Apparently SORBS are under the impression that this is on a dynamic IP address.
Other mail system problem 554-'Service unavailable; Client host [relay.ptn-ipout01.plus.net] blocked by dul.dnsbl.sorbs.net; Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?84.93.230.250';
Other mail system problem 554-'Service unavailable; Client host [relay.ptn-ipout01.plus.net] blocked by dul.dnsbl.sorbs.net; Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?84.93.230.227';
I've had ticket 41276976 open for a week now and it's still happening, could someone see what the problem actually is an let me know when it's likely to be resolved ?
billywatt

[#2]

Hi there,
Just given our networks team a heads up about that one, thanks. I'll let you know when we have more on that, really sorry for the delay.

[#3]

They got a heads up on it last week Matt, I'd prefer some action rather than just being advised that you've told them again.

[#4]

They raised it to Sorbs last week and have been awaiting a reply since then I'm afraid, though I've been assured they're chasing.

[#5]

Quote from: Ravinella

Apparently SORBS are under the impression that this is on a dynamic IP address.

The IP's that are listed are legitimate mail servers of ours so unless they've changed IP recently then they certainly shouldn't be listed as dynamic.
Having said that, the rejection errors strike me as a little odd!

Quote from: Ravinella

Other mail system problem 554-'Service unavailable; Client host [relay.ptn-ipout01.plus.net] blocked by dul.dnsbl.sorbs.net; Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?84.93.230.250'; Other mail system problem 554-'Service unavailable; Client host [relay.ptn-ipout01.plus.net] blocked by dul.dnsbl.sorbs.net; Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?84.93.230.227';

The IP addresses 84.93.230.250 and 84.93.230.227 do not belong to relay.ptn-ipout01.plus.net. They belong to outmx08.plus.net and outmx01.plus.net respectively.
Here's an excerpt from the headers of an email I've just sent via relay.plus.net to an email address hosted off our network:

Received: from [212.159.2.3] (helo=[172.29.48.8])
	 by outmx01.plus.net with esmtpa (Exim) id 1Q7raA-0007on-Vq
	for me@privacy.net; Thu, 07 Apr 2011 16:57:19 +0100 <--- Sent from my local machine to outmx01.plus.net
Received: from outmx01.plus.net ([84.93.230.227])
  by relay.ptn-ipout01.plus.net with ESMTP; 07 Apr 2011 16:57:19 +0100 <-- Sent from outmx01.plus.net to relay.ptn.ipout01.plus.net
Received: from relay.ptn-ipout01.plus.net (relay.ptn-ipout01.plus.net [212.159.7.35])
	(using TLSv1 with cipher RC4-SHA (128/128 bits))
	(No client certificate requested)
	by mxin.mxes.net (Postfix) with ESMTPS id AA4ED2B281C
	for <me@privacy.net>; Thu,  7 Apr 2011 11:57:20 -0400 (EDT) <-- Sent from relay.ptn.ipout01.plus.net to third party mail server

So the only server the recipient should really show any interest in for blacklisting purposes is relay.ptn.ipout01.plus.net. This has the following IP address:

C:\Users\Bobby>nslookup relay.ptn-ipout01.plus.net
Address:  212.159.8.120
Non-authoritative answer:
Name:    relay.ptn-ipout01.plus.net
Address:  212.159.7.35

Which as you can see here, is *not* listed by SORBS.
Quick question, does this only happen when sending to customers of one particular email provider? I can't help but think the problem could be down to one particular mail host using slightly questionable methods to check incoming mail against blacklists?

[#6]

Sorry Bob, missed your reply to this until now.
Only seems to happen when sending emails to people @teamaol.com
Another bounce from them yesterday

            < relay.pcl-ipout01.plus.net #5.0.0 smtp; 5.3.0 - Other mail system problem 554-'Service unavailable; Client host [relay.pcl-ipout01.plus.net] blocked by dul.dnsbl.sorbs.net; Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?84.93.230.227'; (delivery attempts: 0)>