MailEssentials Whitelist and Blacklist
Prevent the auto-whitelist from adding entries when they match entries in the blacklist. With widely disseminated spam, the larger the organization the higher chance that someone will reply.
Jamie Ashfield commented
Furthermore, it would be very useful if the auto-whitelist ignored automated responses to read receipts. Unfortunately we often have a spammer's address automatically added to our whitelist because someone has flicked through their e-mails in Outlook, triggering a read receipt to be sent automatically.
[Comment date: 2012-07-24]
We recently saw this issue and GFI advised us to remove our entire white list as so many spammers addresses had been processed. This would make life alot easier trying to maintain lists.