A catch-all email mailbox is one that captures all the emails sent to invalid email addresses. For instance, if your address is firstname.lastname@example.org, but somebody misspells it and sends an email message 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 thus you will never miss messages because the other party has an obsolete address or has made a typographical error. The drawback of creating a catch-all mailbox is that you may start receiving plenty of unsolicited emails, but this issue can be solved by using anti-spam filtering software. It is also crucial to keep in mind that a mailbox with an activated catch-all functionality cannot forward incoming messages to a 3rd-party email address.