Re: Understanding dsbl?

In article <[email protected]>, John E. Malmberg
<[email protected]> wrote:

> Alan Harper wrote:
> > One of the computers that a colleague uses has an IP in dsbl.org. The
> > IP is 200.79.150.31, and it has been in dsbl for presumably over 1
> > year.
> > 
> > http://dsbl.org/listing?200.79.150.31
> 
> > I assume that this is a dynamically allocated IP, and that it is in the
> 
> It is not listed as a DHCP address in the lookups that I know how to do.
> Is it a DHCP address, if so, that range needs to be submitted to SORBS 
> and NJABL and MAP-DUL for preemptive blocking.
> 
> The rDNS is red-corp-200.79.150.31.telnor.net, which is a generic name, 
> and many networks are now refusing any E-MAIL from generic I.P. addresses.
> 
> If this is a dynamically allocated I.P. the DSBL listing should not 
> matter as it is simply not practical to operate a mail server on a DHCP 
> address.
> 

Every time I think I understand something about mail protocols and spam
filtering, it is demonstrated that I really don't. Perhaps someone can
help me a little bit more here.

A colleague who I work with is in Mexico, so he needs to use telnor.net
as his ISP. He has a windows computer and is sending mail using
Outlook, through a router (don't know which model), and uses
opensourcehost.com as the smtp server. Our web site,
terrapeninsular.org, maps to jag.opensourcehost.com = 69.93.35.100.

He asked me to help because he was not able to send email to some
recipients--and perhaps the problem was that his email was being ID'd
as spam. I am trying to do what I can.

Some headers from a recent email that he sent are:

------------------ RFC822 Header Follows ------------------
Return-Path: <[email protected]>
Delivered-To: [email protected]
Received: (qmail 26283 invoked from network); 23 Jun 2005 16:50:19 -0000
Received: from unknown (192.168.1.101)
  by blade5.cesmail.net with QMQP; 23 Jun 2005 16:50:19 -0000
Received: from jag.opensourcehost.com (69.93.35.100)
  by mailgate.cesmail.net with SMTP; 23 Jun 2005 16:50:18 -0000
Received: from [200.79.150.31] (helo=HIS_ACCOUNT)
   by jag.opensourcehost.com with smtp (Exim 4.50)
   id 1DlUuD-0000n0-0N
   for [email protected]; Thu, 23 Jun 2005 11:50:21 -0500
From: =?US-ASCII?Q?Juan_M._Garcia_Caudillo?=
<[email protected]>
To: "Alan Harper" <[email protected]>
%snip%
X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0)
%snip%
X-SpamCop-Checked: 192.168.1.101 69.93.35.100 200.79.150.31 
X-SpamCop-Disposition: Blocked list.dsbl.org
X-SpamCop-Whitelisted: terrapeninsular.org

I guess the first question is, do you think that 200.79.150.31 is the
IP of his router, or a computer that is somewhere "upstream" of his
computer?

This IP was listed in njabl
http://njabl.org/cgi-bin/lookup.cgi?query=200.79.150.31 and is listed
in dsbl http://dsbl.org/listing?200.79.150.31 . It appears that it is
listed because there was an open relay at that IP in in 2004. Someone,
not me, tried to get it unlisted from dsbl, but dsbl won't unlist it
because telnor doesn't respond to the postmaster mail addresses to
confirm anything. (Telnor doesn't have to care, it is a near monopoly).

The second question is, is there any easy way to see if there is still
an open proxy at this address? As far as I can tell, njabl hasn't
retested the address, and dsbl won't retest it until telnor changes its
procedures (I.e, until hell freezes over).

Right now, whatever was blocking his email is no longer blocking it.
This corresponds with my asking njabl to unlist this address, but I
suspect that it was coincidence.

Any other thoughts about what I can do to increase his chance of
sending emails would be appreciated.

Thanks

Alan