Email domain black listed?

[Kenneth Burgener]

So I thought I was being a good net citizen by routing all my outbound 
email through my ISPs SMTP server (smtp.comcast.net).

But every so often I get bounce back emails saying my email was rejected 
because either my initial IP (which is dynamic), or the SMTP server, or 
some other IP address is black listed.  What is one to do to get his 
emails out.

For example the below email just bounced back to me, saying 63.240.76.22 
is listed in the black hole.  My address today is 67.186.222.247, so it 
wasn't me.  SMTP.comcast.net is 63.240.76.27 so it wasn't the SMTP 
exactly.  So some other mail router at Comcast touched my email and now 
it is a bad email?

Any suggestions?


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A message (from <kenneth at uvlug.org>) was received at 5 Sep 2005 14:44:37 
+0000.

The following addresses had delivery problems:

<fozz at iodynamics.com>
	Permanent Failure: 
550_5.7.1_<fozz at iodynamics.com>..._Rejected:_63.240.76.22_listed_at_blackholes.five-ten-sg.com
	Delivery last attempted at Mon,  5 Sep 2005 14:44:38 -0000

Reporting-MTA: dns; comcast.net
Arrival-Date: 5 Sep 2005 14:44:37 +0000

Final-Recipient: rfc822; <fozz at iodynamics.com>
Action: failed
Status: 5.0.0 
550_5.7.1_<fozz at iodynamics.com>..._Rejected:_63.240.76.22_listed_at_blackholes.five-ten-sg.com
Diagnostic-Code: smtp; Permanent Failure: Other undefined Status
Last-Attempt-Date: Mon,  5 Sep 2005 14:44:38 -0000

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