Re: MTA or SMTP proxy?

2009/7/3 Gábor Lénárt <lgb <at> lgb.hu>:
>> SMTP is a store-and-forward protocol, it does require queues. You cannot
>> simply wave aside this requirement.
>
> I think, protocol itself is just the communication between MTAs (it does not
> store anything itself, MTAs which uses the SMTP can/must store things while
> using SMTP to communicate with other MTAs).As proxy level firewalls has got

Okay, this is getting to semantics. SMTP is your transport for pushing
messages between entities that can store messages. It sounds like you
want some sort of SMTP protocol-level filter. Postfix can't do this in
a comprehensive way such as you describe, but it achieves a lot of
basic, related, important functionality (eg. recipient verification,
because Postfix often performs the mailstore function as well.

At this stage I need to ask: what is your question here? I haven't
tried it, but you may be interested in ASSP, I believe it fits the
definition of an SMTP proxy:
http://assp.sourceforge.net/