A catch-all mailbox is one that captures all the email messages sent to inactive email addresses. For instance, if your 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 created. Just one single mailbox per domain can have this feature activated and in this way you will never miss emails because the other party has an obsolete email address or has made a mistake. The downside of using a catch-all mailbox is that you may begin receiving a lot of unsolicited messages, but this issue can be fixed by using an anti-spam protection solution. It’s also crucial to bear in mind that a mailbox with an activated catch-all functionality cannot forward incoming emails to a 3rd-party address.