L-Soft strongly advises a testing period during which individual spam reports are manually forwarded to the list. It is important to forward the messages in such a way that they are received by the list with the same special MIME structure that identifies spam reports. The sender is immaterial as long as it is authorized to post to the list.

By default, when a spam complaint is received through a Feedback Loop, LISTSERV will:

    1. Immediately delete the user from all local LISTSERV lists, on the first spam report. This does not include Dynamic Query Lists, which are managed outside LISTSERV. 
    2. Not send any notification to the user. 
    3. Add the user to the spam feedback list with the NOMAIL option to keep a record of who has lodged spam complaints. The subscription date is set to the date of the first complaint and the last activity date is set to the date of the last complaint. 
    4. Log a SPAM_COMPLAINT record to the list's change log, if one has been defined. You can use this information to remove the user from Dynamic Query Lists, if you have any such lists that may contain users. 

This ensures that no further mail will be sent to the user and minimizes the risk for further complaints.

You can verify the operation of the feature on the LISTSERV log. Once you are comfortable with your setup, you can redirect all of the ISPs spam reports to the list so that they are processed without manual forwarding.