[BC] Comcast Blacklist

[Sid Schweiger]

>>It is possible that the Comcast webmail system is rewriting the 
original from IP so that it appears that the message is relayed 
directly from the system on the DHCP connection. This would be 
counter to convention. Or it is possible that the Comcast SMTP for 
their webmail system is located within an IP range that is listed 
with ARIN as a cable modem subscriber block. While this does not 
strictly violate any RFC, it is not a recommended practice. IP ranges 
should be allocated in a logical and correctly mapped manner. In any 
event, it does not appear as a malfunction with our scanners.

I have requested further investigation from our Network Operations 
department and a lift of the restriction on the /24 containing the IP 
that has been rejected by our scanners.<<

If you plug comcast.net into www.dnsreport.com, this is what you get
back in the Mail section:

=======================

WARN:  Mail server host name in greeting

WARNING: One or more of your mailservers is claiming to be a host other
than what it really is (the SMTP greeting should be a 3-digit code,
followed by a space or a dash, then the host name). If your mailserver
sends out E-mail using this domain in its EHLO or HELO, your E-mail
might get blocked by anti-spam software. This is also a technical
violation of RFC821 4.3 (and RFC2821 4.3.1). Note that the hostname
given in the SMTP greeting should have an A record pointing back to the
same server. Note that this one test may use a cached DNS record.

mx2.comcast.net claims to be host IMTA12.emeryville.ca.mail.comcast.net
[but that host is at 76.96.30.30 (may be cached), not 76.96.30.116]. <br
/>mx1.comcast.net claims to be host
IMTA07.westchester.pa.mail.comcast.net [but that host is at 76.96.62.61
(may be cached), not 76.96.62.116]. <br />

=======================

"Your E-mail might get blocked by anti-spam software."  Gee...who
woulda thunk it?



Sid Schweiger
IT Manager, Entercom New England
WAAF - WEEI AM/FM - WKAF
WMKK - WRKO - WVEI AM/FM
20 Guest St / 3d Floor
Boston MA  02135-2040
Phone: 617-779-5369
Fax: 617-779-5379
E-Mail: sid at wrko.com