I have a Lync Standard 2013 Server and Lync 2013 edge server, Lync works with all clients on the corporate network, I am able to connect to Lync on my windows 8 phone App(Lync 2010 App) when connect to the corporate wireless, if I leave the client log in then disconnect the wireless and use 3G it still works. If I sign out of Lync then try to login on 3G I am unable to sign it I get error "Can't connect to the server. It might be unavailable. Also please check your network connection, sign-in address, and server address.
I have setup the lyncdiscover on our external DNS and lyncdiscoverinternal on our Internal DNS, I have add all the rules to our TMG 2010 Firewall