I have a setup with a 3CX server v7.1 on WS03 on a hosted server (public IP address). I am connecting Linksys SPA941 VOIP phones from remote offices which have simple broadband connections and cheapo broadband firewall/routers. From one office which has a Thomson Speedtouch 585v7 broadband router the phones work fine - No need for SIP Tunnels or VPNs. However from the other office, although the phones seem to register with the server they don't ring when called. This office has a Netgear DG834G broadband router. I think i can see the source of the problem- When a phone extension 101 registers from the good office, you get the message:- 14:59:06.825 [CM504001]: Ext.101: new contact is registered. Contact(s): [sip:email@example.com:54660/101] In this case, the server knows the phone via the public IP address of its broadband connection which means that it can be rung. Good. When a phone extension 151 registers from the problem office, you get the message :- 14:59:38.450 [CM504001]: Ext.151: new contact is registered. Contact(s): [sip:firstname.lastname@example.org:5063/151] The registration is reporting 192.168.1.109 which is the temporary IP address of the phone on the LAN in the office, which cannot be routed from the server. Bad. Any ideas ?