In addition we configure the Exchange client to DELIVER INTERNET mail via our UNIX server and not via the Exchange server.
The other site has both a X.400 connector and a INTERNET MAIL CONNECTOR configured because they have their own INTERNET mail gateway which is connected to their Exchange server. Therefore ALL their clients receive both INTERNET and INTERNAL mail from one source i.e. their Exchange server unlike us where we have 2 sources.
Now finally I get to the problem that we are experiencing, our users have become clever and they try their luck by sending INTERNET mail and since their e-mail client only has ONE source i.e. EXCHANGE, the EXCHANGE server receives this request to send a INTERNET mail and since NO IMC connector exists in our site, the message is send via X.400 to the other site which has an IMC and then it in turn processes this request and sends out the message via this gateway.
