more on Comcast blocking personal mail servers

[David Farber <dave () farber net>]

Begin forwarded message:

From: Ron Guerin <ron () vnetworx net>
Date: April 9, 2006 7:03:35 PM EDT
To: alberti () sanction net
Cc: dave () farber net
Subject: Re: [IP] more on Comcast blocking personal mail servers

Robert Alberti wrote:
> > From: Ron Guerin <ron () vnetworx net>
> > You don't mention who your ISP is, however, if Comcast is under the
> > impression you're on a residential IP address, odds are they got this
> > information from _your_ ISP, who is, in effect, telling Comcast to  
> > block
> > your mail.  Does your agreement with your ISP prohibit the running of
> > servers from your account?  If so, you have your answer, which is  
> > that
> > you're violating your agreement, and Comcast knows this because  
> > your ISP
> > has published their residential IP addresses for the express  
> > purpose of
> > allowing other ISPs to refuse mail coming from those addresses.   
> > If your
> > service agreement does not prohibit the operation of servers, you  
> > still
> > should investigate whether your ISP has published their  
> > residential IP
> > space for blocking purposes.  Many, if not most residential blocking
> > lists are based on self-published IP ranges.
>
> I have a static DSL IP from visi.com which permits the operation of
> servers on my account.  I suspect although I do not know for sure (nor
> did the Visi technician to whom I spoke) that the fact that my reverse
> DNS name is "sanction.dsl.visi.com" that either the discrepancy  
> between
> my mailhost name "sanction.net" or the presence of 'dsl' in the string
> are triggering the rejection.  I'm trying a reverse-DNS of
> 'sanction.net' to see if this fixes the problem.

That may well fix your problem.  It all depends on the policy over at
Comcast, which as you say, is in all probability, unpublished.  I do
know of some who attempt to dynamically block based on parsing the
returned value of the reverse lookup, and indeed, it is considered a
sign of both competence and intent to run a mail server by some mail
service providers if you've had your reverse lookup changed to
something not "generic" to the given ISP.  As a last resort, you could
try contacting Comcast for a whitelisting.  Given that you are not
prohibited from running servers, you certainly have grounds to protest
your blocking.

> I like Karl's solution of obtaining a block of IP addresses from Jon
> Postel, however the hereafter keeps rejecting my e-mail requests for a
> block of my own.

I wish we all had what Karl has. At least I wish *I* did. ;)

- Ron


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