A catch-all mailbox is one that collects all the email messages sent to invalid addresses. For instance, if your email address is firstname.lastname@example.org, but someone mistypes it and sends a message to email@example.com, it will still be received in the catch-all mailbox that you have set up. Only one mailbox per domain can have this feature enabled and thus you’ll never miss messages because the other party has an obsolete address or has made a spelling error. The downside of configuring a catch-all mailbox is that you may start receiving a lot of unsolicited bulk email messages, but this issue can be fixed by using anti-spam filtering software. It is also important to keep in mind that a mailbox with an active catch-all feature cannot redirect incoming emails to a third-party email address.