I recently upgraded a client and we of course have port 80 as the default for accessing their portal home page. They also have Exchange with OWA being used. When the users attempt to access portal subsite via HTTPS they are redirect to OWA which I am assuming is also on port 80. This DOES NOT happen to all sites, only some sub sites. The portal is on one site collection. Thanks for any advice.Hank Farlow

Sounds like you will need to either assign IP Addresses to each of the IIS Websites instead of using unassigned, or you can use host headers for each of those sites also...but you will need to make sure that DNS is working correctly.