A catch-all email mailbox is one that gathers all the messages sent to invalid addresses. For example, if your address is firstname.lastname@example.org, but somebody miswrites 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 name can have this feature enabled and thus you will never miss messages because the other party has an obsolete address or has made a mistake. The disadvantage of creating a catch-all mailbox is that you may start receiving plenty of unsolicited messages, but this problem can be resolved using an anti-spam protection solution. It’s also important to know that a mailbox with an enabled catch-all functionality cannot forward inbound email messages to a 3rd-party email address.