A catch-all mailbox is one that gathers all the emails sent to inactive email addresses. For example, if your address is firstname.lastname@example.org, but somebody misspells it and sends an email to email@example.com, it will still be received in the catch-all mailbox that you have configured. Just one single mailbox per domain name can have this feature activated and thus you’ll never miss emails because the other party has an obsolete email address or has made a mistake. The drawback of having a catch-all mailbox is that you may start receiving a lot of unsolicited bulk email messages, but this issue can be fixed using anti-spam protection software. It’s also essential to keep in mind that a mailbox with an activated catch-all feature cannot forward incoming messages to a 3rd-party email address.