I have a Exchange 2003 front/back end setup and I have a requirement that we allow external members of a distribution list to send to everyone in the dist. list, even other external members. That's relaying, so I'm trying to figure out a way to allow this to happen and not make both of my Exchange servers open relays.
My testing so far indicates that making the internal server an open relay doesn't work because the external server refuses to relay the external recipients. I don't want to make the external server an open relay because we'll get blacklisted.
Does anyone have ideas on how to solve this problem?