When someone sends you an email for the first time, Box Trapper responds back asking them to reply to prove their not a spammer or bot. If they reply they can be white listed and never have to do it again. The concept, relies on the fact that spammers and bots will not reply to the email BoxTrapper sends and therefore can be determined as spam. One problem with this is if you get emails from banks, businesses, etc. that use a firstname.lastname@example.org and they will not reply. Since they do not reply you will not receive the email they sent.
You can also manually add any addresses of people you already correspond with (your address book in your mail client is a good place to start) to the white list, so you don’t have to bother them with getting approved. Pay attention to the format of the addresses listed above the white list box to avoid errors.
In theory, BoxTrapper sounds like a great solution but may not be the best tool for everyone to use. We recommend using SpamAssassin instead.
Note: one odd behavior of the BoxTrapper is that the “enable auto whitelisting” feature does not remain checked if you are using it from the webmail interface. If you are unsure, check that setting from the mail area in cpanel and you will see the true setting.