Dear Friends , I have installed 3CX phone system in our Win Server 2003 in our company network , we have no problem inside our network but for our external extension although we use from 3CX tunnel , but we only can work with 3CX client or 3CX soft phones and none of our Hard IP Phone (Ex. Dlink Dph 150S) could work well , these IP phone register through our tunnel with in our internet connection but sometimes had no ring (We couldn't call these extension some times) and in any case we heard no voice after connect to them . Please note that these IP phone works well inside our local network . please help if anybody knows any solution . thankyou.