cpanel mailman feedback loop strips email address

I have several customers using a combination of mailman and cPanel. In order to track spam complaints I have various feedback loops in place with Comcast, AOL, Roadrunner, etc…

Invariably, when someone on a mailman list complains of spam through their ISP and I receive a message back from the feedback loop, they (Comcast, AOL, etc.) strip out the complainers email address, making it impossible to trace and fix the problem.

To address this problem, the email address can be included in the footer of each message in the form of an encoded URL string where the AT (@) sign is replace with it’s hex code of %40. The feedback loops don’t recognize this syntax and consequently do not strip the encoded email address, allowing me to remove the complainers from the mailman list, or investigate further.

By default, cPanel and mailman do not allow the customers to include this encoded signature, so the following must be done.

Edit the file located at
/usr/local/cpanel/3rdparty/mailman/Mailman/mm_cfg.py
And make sure the following is at the bottom of the file.

Once this is done, the customer can go into their mailman settings, and place the following code into the signature of each message for the list.

Unsubscribe: %(user_optionsurl)s

This will include the encoded email address in the string. Credit to the following cpanel thread that allowed me to address this problem.

http://forums.cpanel.net/f34/mailing-list-field-50459.html