A catch-all mailbox is one that collects all the emails sent to non-existent email addresses. For example, if your address is firstname.lastname@example.org, but somebody miswrites it and sends an email to email@example.com, 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 in this way you’ll never miss emails because the other side has an obsolete address or has made a spelling error. The disadvantage of using a catch-all mailbox is that you may begin receiving lots of spam email messages, but this issue can be fixed by using an anti-spam protection solution. It is also vital to bear in mind that a mailbox with an active catch-all feature cannot redirect incoming email messages to a third-party email address.