I'm trying to get Http to Https redirect to work Externally for webmail.mydomain.com using reverse proxy with the latest Squid3 version. The redirect works fine internally through the LAN interface. In order for it work externally do I need to setup reverse proxy using the General Tab, Servers Tab and  Mappings Tab?

For the General Tab, what do I need to enter for the External FQDN. How about the User defined reverse proxy IPs, do I enter the private subnet 172.16.0.5 and or the public IP address for webmail.mydomain.com e.g. 216.xxx.xx.xxx.

Do I need to setup both the Squid Reverse Http settings and Squid Reverse Https settings?

Your help would be much appreciated.