I've been researching information on using TLS for inbound SMTP traffic. I've found a variety of links from MS and one on msexchange.org, but none of them are a very good guide to follow. I'm using Exchange 2003 SP2 with 1 front-end server that handles all inbound mail, and two back-end servers. There is 1 SMTP virtual server per exchange box. I want to be able to allow TLS encrypted e-mails from one particular company. I'm not sure if I can do this via my existing SMTP virtual servers or I need to create new ones. Beyond that, it seems that I need to get an X.509 certificate and then make some authentication changes in the SMTP virtual server and everything should work. The documentation I've found has not been the greatest, so I'm not sure if there is more to it. Does anyone have any good articles or could offer me some assistance?