Cox Communications – Blocking URL’s Within Message Body??

I was helping a client troubleshoot a deliverability issue with Cox Communication the other day and found something very odd.  The issue was that all messages being sent to @cox.net recipients was never reaching the inbox.  The messages were not being bounced back so there was no bounce error to reference back to and of course without that Tech Support is less opt to help troubleshoot.  The messages do not appear to be blocked for domain or IP reasons, and it doesn’t seem to be content related, but it does appear to have something to do with the message itself.  Here is the scenario and what we tried with the results:

* Simple text message no links – delivered to @cox.net mailbox

* Simple text message with a hyperlinked word (i.e. Click here) – delivered to @cox.net mailbox

* Simple text message with a hyperlink written out in the message body (i.e. http://www.mydomain.com/link.php) – not delivered to @cox.net mailbox

* Simple message with average size image and no links – delivered to @cox.net mailbox

* Simple message with average size image with a hyperlinked word (i.e. Click here) – delivered to @cox.net mailbox

* Simple message with average size image with a hyperlink written out in the message body (i.e. http://www.mydomain.com/link.php) – not delivered to @cox.net mailbox

**NOTE** – We used the same url for the hyperlink throughout all of our testing.

Once we removed the hyperlink from within the message body and replaced it with hyperlinked text, all messages from the client’s IP/domain were delivered.  Has anyone else had or seen this issue before?  This is the first time that I have seen this technique by anyone to block messages.  This technique of blocking would make it difficult for anyone trying to pass a hyperlinked url in their message for a copy and paste reason or for text messages.

I have fired off an email to the postmaster at Cox and will post back the response one I receive it.  If you have any experience with this, please let me know by commenting back or by sending me a message (mweisel at goldlasso dot com).