BoxTrapper

Box Trapper returns a confirmation email to senders, who must reply before their email is delivered (to you). Any email user can sign into webmail and just before you select the mail program, you will see an icon for BoxTrapper. You can enable/disable the trapper, edit the whitelist and blacklist, and you can review the mail logs to see what emails are not being delivered. 

BoxTrapper logs taking up too much space?
You can set how many days BoxTrapper will keep the mail logs on the server: 

1. Simply click on "Boxtrapper Spam Trap" under Email Managment, 
2. Click "Manage" next to the email address you want to adjust. 
3. Click "Configure Settings" 
4. Type in a new number into the third text field "How many days should logs and messages in queue be kept" and click "Save".