A catch-all email mailbox is one that captures all the emails sent to inactive addresses. For instance, if your email address is firstname.lastname@example.org, but somebody miswrites it and sends a message to email@example.com, it will still be received in the catch-all mailbox that you have set up. Only one single mailbox per domain name can have this feature enabled and in this way you will never miss messages because the other side has an out-of-date email address or has made a spelling mistake. The disadvantage of creating a catch-all mailbox is that you may begin receiving plenty of spam emails, but this issue can be resolved using anti-spam protection software. It’s also important to keep in mind that a mailbox with an enabled catch-all functionality cannot redirect incoming email messages to a third-party address.