A catch-all mailbox is one that captures all the email messages sent to nonexistent addresses. For instance, if your address is email@example.com, but somebody misspells 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 single mailbox per domain can have this feature activated and in this way you’ll never miss messages because the other party has an obsolete address or has made a mistake. The downside of having a catch-all mailbox is that you may start receiving lots of unsolicited email messages, but this issue can be rectified by using anti-spam protection software. It is also crucial to keep in mind that a mailbox with an active catch-all functionality cannot redirect incoming emails to a third-party email address.