[plug] Sendmail - Smart host not working

[Andrew Carson]

Hi all,

Have a very perplexing problem here.. hoping someone has seen similar or knows
the answer.
sendmail-8.11.6-25.73 on a RH7.3 box  It sits behind a firewall and has no
access to external DNS, so cf file is compiled with smart host entry, pointing
to a machine that is running fine as a smart host for another mail server.  I
also have accept_unresolvable_domains and accept_unqualified_senders compiled
into the cf file.   The smart host is running exim.  I have the appropriate
settings in the exim config file, that is: host_accept_relay and route_list.
The problem.  Outgoing mail, even with the smart host set, *still* gets stuck
in the queue with a "deferred" error due to host map: lookup for the
destination domain, and mail coming in passes through the exim mail gateway
without a problem.. and then gets stuck at sendmail with the same problem. 
I've been ripping my hair out for days on this.. does anyone have an idea?

Thanks,

Andrew.