Postfix, per-user relaying...

[Andrea Giuliano]

Dear all,

I'm running Postfix on Breezy with no problems, but since I'm behind a 
firewall I have set the relay_host option to tell Postfix what host must 
be used as the relayer for mail going outside my system (almost all mail).

This is not a problem for me, but now I'm asked to create some e-mail 
accounts in order to allow some students to learn how to use mail 
clients. This is pretty easy, but I don't want allow them to send mail 
outside my box (they just have to send mail between them, and just for a 
few days).

I'm wondering if there's a way to allow relaying to some users and not 
to others.

Another solution I thought of is prevent some users access to non-local 
delivery, but till now I didn't find out how to accomplish that.

Best regards.

-- 
Andrea Giuliano, Ph. D.
ICCU - Istituto Centrale per il Catalogo Unico
Viale Castro Pretorio 105, Rome - ITALY
Tel. +39 06 49210403, Fax +39 06 4959302