Hi! We're being approached by a networking company whose customers need Smart Host services. i.e. they run Exchange servers and are being blacklisted because some of the Exchange servers are assigned dynamic IP addresses. They want the Exchange servers to relay through us, so as not to get blacklisted.
I don't quite understand how they could even be receiving email reliably with a dynamic IP address on their mail server; I'm checking with the networking company now. Maybe they're using some kind of dynamic DNS service? Anyways, I'm thinking about how to provide this service without becoming an open relay. I need the Exchange server to authenticate to Imail somehow. There's also the issue of outbound port 25 being blocked by many major ISP's. We've toyed with the idea of requiring SSL connections on port 465 from the Exchange server, but I'm not sure of what kind of server-to-server authentication I can set up in Imail to prevent us from becoming an open relay. Is someone else already doing this with Imail? What solution have you come up with? Thanks, Adam
