Define catch-all email address

[Timotheus Pokorra]

Hello,

I know that catchall email addresses are not such a good idea because
they make you receive all sorts of spam messages.

But in case the customer wants it, how would I configure it?
I can see on the mykolab FAQ (https://mykolab.com/faq#catch-all) that
it must be possible, but I have no idea where to configure this, even
manually?

Thanks for any advice,
  Timotheus