Using whitelists and blacklists can certainly assist in blocking unwanted messages and allowing wanted messages to get through, but they are not perfect. Some Internet service providers also sometimes use whitelists to filter incoming email, but it’s usually end-users that set spam filters to actually delete all emails from sources not on the white list. Regardless of what the feature is called, mail from the listed email addresses, domains, and/or IP address on such a whitelist should always be allowed through. If it is not exclusive, it prevents email from being deleted or sent to the junk mail folder by the spam filter. If a white list is exclusive, only email from those on the white list will get through.

Some services simply require accepted addresses be in one’s address book, while others require that you manually add addresses to a particular 'approved', “safe”, or 'allowed senders' list. Your ' whitelist' is the list that contains the email addresses of those you do in fact deem acceptable to receive email from and do not want to automatically go to the trash folder. Many spam filters that come with email clients have both white and black (or block) lists of senders to check for in emails. How can you “whitelist” emails you want to receive? When subsequent resends or replies back are also dumped unceremoniously by their email, this compounds the problem of reaching them. Even 3D Inspection System users occasionally contact us saying they never received a recent software subscription or reply to a question or ticket. In an understandable attempt to eliminate annoying spam, over-zealous email filters can inadvertently dump emails you want to receive, including newsletter subscription requests or important emails or replies you requested.

Gmail spam folder missing