Comcast and mail header errors?

Ben Scott dragonhawk at gmail.com
Mon Mar 20 22:29:58 EST 2006


On 3/20/06, Dan Jenkins <dan at rastech.com> wrote:
> I grepped through my umpteen stored emails and found a number of
> instances. All involving Comcast. Some of the "misconfigured servers"
> included ATT.NET and COMCAST. So, their own servers are sometimes
> "misconfigured" too.

  Yah, I saw that too, but in all cases, it appeared that someone had
configured their own MX to masquerade as "comcast.net".  Presumably,
these people are on a Comcast feed and using a cheap kludge to make
their domain name match their mail host.  If Comcast is complaing
about HELO not matching DNS, that would properly trigger it.  It's
hardly Comcast's fault that people are doing that.

  In theory, a sending SMTP should neve" be the domain name
"comcast.net".  Sending SMTPs will be domain names like
"foo.comcast.net", but never the 2LD.

>>  As a wild guess, I'd say Comcast is throwing that in when the name
>> given in the HELO does not resolve to the IP address of the
>> sender-SMTP.
>
> That's what I've believed, though I have no apparent reason, now that I
> think about it. ;-)

  Well, my wild guess was based on what the "sender" host names I saw,
which all appeared to be suspect that way.  That hardly counts as
evidence at all, though.

> Comcast is not near the top of my list of authoritative sources. :-D

  Heh.  Indeed.  :)

-- Ben



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