A catch-all mailbox is one that captures all the email messages sent to non-existent email addresses. For instance, if your email address is email@example.com, but somebody mistypes it and sends an email to firstname.lastname@example.org, it will still be received in the catch-all mailbox that you have created. Only one mailbox per domain can have this feature enabled and thus you’ll never miss messages because the other side has an obsolete address or has made a spelling mistake. The negative aspect of creating a catch-all mailbox is that you may start receiving a lot of unsolicited bulk messages, but this issue can be resolved using anti-spam protection software. It’s also crucial to keep in mind that a mailbox with an activated catch-all functionality cannot redirect incoming emails to a 3rd-party mailbox.