I have been seriously studying my butt off for the past few weeks, have read all of Kevin's slides, forums, everything I could get my hands on and even passed the certification test so I thought I had this stuff pretty well under control until yesterday when we tried to do some remote connectivity work and have run into nothing but problems. The scenario is that we have two offices setup by themselves and everything is working perfectly internally and the SIP trunks are working flawlessy. But yesterday we are out of town and wanted to do some bridging and remote connections, and this is where everything is falling apart. Both systems are using v8 RC2 on XP Pro SP3 and RC2 versions of 3CX Voip Phone and 3CX Assistant. Both firewalls were initially setup identically per Kevin's firewall slide with the following ports forwarded: 5060 UDP 9000-9049 UDP 5090 Both Bridging the two systems together, slave system always was reporting destination tunnel doesnt appear to be running 3CX Assistant logs in perfectly with or without tunnel on 3CX Voip Phone will not connect to server, always returns destination not found. After searching and searching, we then added the following port forwarding: 5480-5486 Both At this point we had made some progress: Bridge was up and functioning 3CX Assistant logs in perfectly with or without tunnel on 3CX Voip Phone connects with or without tunnel on Zoiper Softphone registers after several minutes but is not usable Cisco SPA509G registers after several minutes but is not usable Once registered, if you try and place a call, Zoiper appears to dial and then eventually times out with the following log entry: 07:26:47.130 [CM500002]: Unidentified incoming call. Review INVITE and adjust source identification: INVITE sip:email@example.com;transport=UDP SIP/2.0 Via: SIP/2.0/UDP 192.168.2.101:5060;branch=z9hG4bK-d8754z-4ab92aece2e64663-1---d8754z-;received=126.96.36.199 Max-Forwards: 70 Contact: <sip:firstname.lastname@example.org:5060;transport=UDP> To: <sip:email@example.com;transport=UDP> From: <sip:firstname.lastname@example.org;transport=UDP>;tag=865be671 Call-ID: NjgwM2I2NjU1ODZmOTM5OTU0YjUzZTBlMjcwOWVlOGE. CSeq: 1 INVITE Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, MESSAGE, OPTIONS, INFO, SUBSCRIBE User-Agent: Zoiper rev.4829 Content-Length: 0 While Zoiper trying to register, I am getting this message: 07:41:17.552 [CM302001]: Authorization system can not identify source of: SipReq: SUBSCRIBE email@example.com tid=93900e1ff1e5e931 cseq=SUBSCRIBE firstname.lastname@example.org:5060 / 1 from(wire) The Cisco509G acts a little different and although it takes a almost a minute, it does register, trying to call out results in the following message: 07:43:35.365 [CM500002]: Unidentified incoming call. Review INVITE and adjust source identification: INVITE sip:email@example.com SIP/2.0 Via: SIP/2.0/UDP 188.8.131.52:38743;branch=z9hG4bK-e7a96aa0 Max-Forwards: 70 Contact: "101"<sip:firstname.lastname@example.org:38743> To: <sip:email@example.com> From: "101"<sip:firstname.lastname@example.org>;tag=855c462256300d53o0 Call-ID: email@example.com CSeq: 101 INVITE Expires: 240 Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER Supported: replaces User-Agent: Cisco/SPA509G-7.1.3 Content-Length: 0 What I am pretty confused about is why the 3CX Assistant would connect over the tunnel and the Softphone wouldnt at first when I followed the firewall instructions in Kevin's slides to the letter and had to open more ports. Second, why will a phone that works perfectly in the offices wont work remotely? Third, why Zoiper softphone won't work internally or externally I hope I have provided enough information here to help shed some light on this.