Like IIS, UWS allows applications sharing non-SSL ports of the same IP address, by specifying different hostnames for each application. This is possible because HTTP.SYS driver looks for the "Host" header in the request, and routes request accordingly. When SSL is used, request is encrypted, and even HTTP.SYS router can't look inside the request. Therefore, all SSL endpoints have to have either unique IP address, or port.

Best regards,
UltiDev Team.