A catch-all e-mailbox is one that gathers all the emails sent to invalid addresses. For instance, if your address is email@example.com, but somebody misspells it and sends an email to firstname.lastname@example.org, it will still be received in the catch-all mailbox that you have set up. Just one single mailbox per domain can have this feature enabled and thus you will never miss messages because the other side has an out-of-date email address or has made a typo. The downside of configuring a catch-all mailbox is that you may start receiving plenty of spam, but this issue can be fixed by using an anti-spam filtering solution. It’s also crucial to bear in mind that a mailbox with an enabled catch-all functionality cannot redirect incoming email messages to a third-party address.