Redirect based on client IP address

Hi All,

I have an existing Reverse Proxy (IIS ARR) setup for Lync 2013. I want to add another redirection for a different site based on the client's IP address.

If they are on the LAN (10.10.10.x) then redirect to http://auth1/login.asp

If they are on WAN (any other IP address) then redirect to https://auth1.contoso.com/login.asp

Any help would be great! thanks :)