The "Catch-all" setting on a domain defines what our servers will do for all emails that we receive to addresses other than the forwarding aliases that you setup.
By default, this setting is to "fail", which means that anyone who sends to an address that is not configured will receive an error that the customer address does not exist.
You can, however, set that to "blackhole", which means that anyone who sends to an address that is not configured will not receive an error, and the message will be discarded by our servers.
The third option, which we don't recommend, is forwarding all of those emails to another email address.
The reason that we advise against configuring a catch-all address is that most spam messages are sent to random first names and other generic email addresses on a domain, like [email protected], [email protected], etc. As a result, you'll receive a lot more unwanted messages and this may result in deliverability issues for messages that you actually want to receive through your domain.
