Hello, This is not a firewall issue. Im unable to make calls from my softphone outside my firewall (on the Internet). But I can make calls to that extension and talk from inside of the firewall. The softphone sais Forbidden when I try to call one of my extensions (no 10). I get following in the log ("my external IP" is my external ip xxx.xxx.xxx.xxx) : 13:33:24.953 [CM503008]: Call(73): Call is terminated 13:33:24.953 [CM502001]: Source info: From: "3CXPhone"<sip:16@"my external IP":5060>;tag=3259ed12<sip:10@"my external IP":5060> 13:33:24.953 [CM503013]: Call(73): Incoming call rejected, caller is unknown; msg=SipReq: INVITE 10@"my external IP":5060 tid=7e1e2432237bac44 cseq=INVITE firstname.lastname@example.org:5070 / 2 from(wire) 13:33:24.578 [CM500002]: Unidentified incoming call. Review INVITE and adjust source identification: INVITE sip:10@"my external IP":5060 SIP/2.0 Via: SIP/2.0/UDP 18.104.22.168:5070;branch=z9hG4bK-d8754z-d94767345b6eaf5f-1---d8754z-;rport=5070 Max-Forwards: 70 Contact: <sip:email@example.com:5070> To: <sip:10@"my external IP":5060> From: "3CXPhone"<sip:16@"my external IP":5060>;tag=3259ed12 Call-ID: ODNiMzYxNmJiNTA0MzMzMWM4NjI5Yjg1OTMzNzQyMjI. CSeq: 1 INVITE Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REGISTER, SUBSCRIBE, NOTIFY, REFER, INFO Supported: replaces User-Agent: 3CX Phone 7.0.4526.0 Content-Length: 0 13:33:24.578 [CM302001]: Authorization system can not identify source of: SipReq: INVITE 10@"my external IP":5060 tid=d94767345b6eaf5f cseq=INVITE firstname.lastname@example.org:5070 / 1 from(wire) What can I do to make this work. I can call my extension that is outside of the firewall and I can talk both ways BUT I cant start the call from the extension outside the firewall. Hope anyone knows the answer.