I've done this a couple of times now and I still can't seem to get this to work. The only thing I've changed is the name from www.mydomain.com <http://www.mydomain.com/> to mail.mydomain.com. So now when I go to https://mail.nusolutions.biz/exchange I get the security alert and page not found but with the following error: 500 Internal Server Error - The target principal name is incorrect. (-2146893022) Internet Security and Acceleration Server After reading the article posted here: http://www.isaserver.org/tutorials/error505.html I've found that the web publishing rule doesn't resolve mail.mydomain.com, the name that's listed as the FQDN or common name in my certificate for this mail server. I have split DNS in place and it appears to be working. The email server resides in the domain and sits on the internal LAN unlike the web server which resides on the same network but sits in a separate workgroup. All public DNS records reside on this web server including one for mail.nusolutions.biz - 205.179.x.x. My question is how do I get the web publishing rule to resolve to mail.mydomain.com? The article says to "configure the web publishing rule to use the FQDN listed in the web server certificate's common name entry". This IS how it's configured and that name is mail.nusolutions.biz. I also tried the internal IP of this internal email server. What am I missing here? Thanks