[Mimedefang] Allowing only certain sender/recipient pairs

[David F. Skoll]

Cormack, Ken wrote:

> I have been asked to investigate setting up a solution to allow only certain
> senders... to email only certain recipients, with any non-approved
> sender/recipient messages being rejected.

Does the person who asked you to do this understand how easy it is to
forge the sender address?  It's a lot of work for almost no security...

> Has anyone ever set up something like this?  What database types were used
> to contain the lookup tables for valid sender/recipient pairs?  What kind of
> performance hits were encountered?  And I assume "stream by recipient" was
> needed to allow a message to be passed to an allowed user, yet not passed to
> a disallowed recipient.

If you do all your processing in filter_recipient, you don't need to
use stream_by_recipient.  Just accept or reject each recipient as
appropriate.  Note that if people connect directly to the MIMEDefang
box with e-mail clients, they may get nasty error messages.

> David - Is this a feature available in the Can-It products?

CanIt-PRO can do it (in a rather cumbersome way -- it wasn't really designed
for that.)

Regards,

David.