I can't see anything in the manual that explains this sufficiently.
Can anyone enlighten me as to the difference between a Local Domain and a Permitted Domain in the Email -> Email Configuration -> Receiving Email -> Anti-Relay settings screen?
what about the online help of the appliance?
Permitted domain in that section might be a domain that is permitted to relay to outside parties thru the appliance whereas Local Domain is a domain that must be accepted and forwarded to a given host internally (SMTP gateway for example).
A permitted domain will always be accepted and delivered.
A local domain will be accepted but is then subjected to scanning, and may be delivered, dropped, quarantined, etc.
That has been my understanding of it, and what best fits what is in the training slides. I would go test it to make sure, but my lab environment is having some issues at the moment.
please take a look at Meg Best Practices manual. On page 23 it properly defines permitted domain with regards to anti-relay (I wish it were defined so in the product manual as well :-( ):
I hope this further clarifies everything.