A catch-all mailbox is one that collects all the email messages sent to inactive email addresses. For example, if your address is firstname.lastname@example.org, but somebody mistypes it and sends an email message to email@example.com, it will still be received in the catch-all mailbox that you have created. Just one mailbox per domain can have this feature activated and in this way you’ll never miss messages because the other party has an obsolete email address or has made a spelling mistake. The disadvantage of having a catch-all mailbox is that you may start receiving plenty of spam email messages, but this issue can be rectified using an anti-spam protection solution. It is also essential to keep in mind that a mailbox with an enabled catch-all functionality cannot redirect inbound emails to a 3rd-party email address.