Hy!
The Outlook Anywhere (RPC over HTTP) lets client connect with their Outlook to Exchange from outside of the LAN for example over the internet. When I set up the OA there are two URL what I can configure, ExternalHostname and InternalHostname. I think the clients will be use the ExternalHostname URL parameter when they are on the internet. And when clients use the InternalHostname URL? When the clients connect to the Exchange in LAN? I tested it, and remove the parameter from the InternalHostname URL, and the client still can connect to the exchange in LAN.
Thanks.