On 20/12/2019 09:43, Andy Burns wrote:
e.g. for some sites I have configured one server to accept email without
authentication but for delivery to local email ddresses only,

That is a mail server.

and
another server that requires authentication, but will relay to external
addresses.

That is a relay.


--
€œThose who can make you believe absurdities, can make you commit
atrocities.€�

€• Voltaire, Questions sur les Miracles Ã* M. Claparede, Professeur de
Théologie Ã* Genève, par un Proposant: Ou Extrait de Diverses Lettres de
M. de Voltaire