[Mimedefang] Interaction between filter_relay and sendmail MAIL FROM: name resolution

[Rajesh Bhandari]

We have some machines that need to relay mail through our mailhub.  The
mailhub is running MD2.21 and Sendmail 8.12.5.  The key point is that
these machines are not in DNS.  Their IP address range IS on a local
subnet.

I was going to set them up to relay using the filter_relay function. 
How does this interact with the sendmail MAIL FROM behavior, where it
does a reverse lookup on the IP and does not allow the connection if it
cannot be resolved.  Needless to day, I am reluctant to use
FEATURE('accept_unresolvable_domains').

So, would returning a 0 for filter_relay allow these machines to
relay?

Thanks,
Rajesh