Hi all, I have a following setup: Internet line coming to Cisco router (public, static IP) 3CX box behind NAT (IP - 10.10.10.202), tcp ports 5060, 5090; udp ports 5060,9000-9015 forwarded to the machine. Current ver 6.1.0 Linksys SPA 3102 voice gateway (IP - 10.10.10.137 connected to WAN port) with an outside POTS line connected I've tried all possible combinations that I could think of in order to get outside clients (also behind NAT) to make calls but without much success. Registration passes with STUN enabled on the phones, but in best case when making call only one side can be heard. I could go on about the things I've tried, but before I go into that, I'm just wondering if this can be generally achieved? Unfortunately I cannot assign public address to any of the machines, but I can forward any port. Local calls to outside POTS network and vice versa works fine. If this can be done, can some one point me to the correct configuration, or to the nature of problem? Greatly appreciated!