A catch-all e-mailbox is one that gathers all the emails sent to non-existent email addresses. For example, if your email address is email@example.com, but someone miswrites it and sends a message to firstname.lastname@example.org, it will still be received in the catch-all mailbox that you have set up. Only 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per domain can have this feature activated and in this way you will never miss emails because the other party has an outdated address or has made a typographical error. The downside of setting up a catch-all mailbox is that you may begin receiving a lot of junk email messages, but this issue can be rectified by using an anti-spam filtering solution. It is also vital to bear in mind that a mailbox with an enabled catch-all feature cannot forward inbound email messages to a 3rd-party email address.