

The blow graphic depicts the port change and the placement of the Reverse Proxy Device. The reverse proxy receives internet traffic on port 80 and 443 and then forwards that traffic to the Skype4B Front End/s on port 44. Now that we know the purpose of the two web sites, this is really where the Reverse Proxy comes into play. Skype for Business Server Internal Web Site – which is bound to port 443 and 80.Skype for Business Server External Web Site – which is bound to port 80.You can view the port bindings by selecting the site and ‘Edit Bindings’

Using differencing ports also allows the Skype4B Front Ends to use a single IP address.

Skype for Business differentiates these sites by using different ports: Not all Skype4B Web Services are designed to be exposed to the internet – examples would be the Skype4B Control Panel and the Response Group Configuration page. Why are there separate Web Sites for Internal and External Web Services? One web site for Internal and one for External. Let’s take a quick look at the IIS settings of a Front End Server in my lab you will see that there are two different IIS sites (Image below).
