Any Comcast RBL/Email admins?


Our two outbound mail gateways have been blacklisted by Comcast, and the normal form ( is returning a weird error. See below.

Your request for IP block removal has been denied for the following
- You have been blocked from emailing the Comcast network because
we have determined that you are sending email from a
dynamic/residential IP within the Comcast domain. Comcast does not
allow subscribers to send email from a mail server other than All mail should be sent through Comcast's mail
server. For information on configuring your machine to use, please follow the link below.

Now, I'm pretty sure that our IP address block (147.9) is not part of Comcast, and we've been unable to get a hold of a person that can help explain this. Any help would be most appreciated.


Michael Grinnell
Network Security Administrator
The American University