Hi, I am quite new to ip tlephony and am just about a week or 2 learning this stuff. So i bought myselve a nice cisco 7960 SIP and got a SIP account with a provider. The Cisco phone allmost worked instandly with budgetphone.nl I had quite some trouble getting the line registered. Firewall logs showed some hits from their sip server from udp 5060 to some low udp ports 1027, 1028, 1034. I do not know why this happens but after creating a global translation from outside to my inside 3CX machine and allowed all udp traffic from my sip providers server back in. It worked instantly. So I thought i share this experiance with you all. If you have other or similar experiances please share them.