My SIP trunk provider (MyNetFone) does authentication based on the public IP and DID in the INVITE header. I'm having problems making outgoing calls - the SPA525G phone says Connecting, and eventually Temporarily not available. I enabled verbose logging and noticed that the INVITE header has my internal IP address - is that a function of the phone, 3CX, or my router? I rang up MyNetFone and the tech I spoke to did a trace while i made a call, and said yeah, the problem is my internal IP address in my INVITE header - it needs to be my public IP address. How do I change that? The router I intend to use is a pfSense box, I also did testing with a Linksys RVS042 and it did the same thing. here is the log, stripped of phone numbers: Code: 17:10:19.539 [CM503020]: Normal call termination. Reason: No answer 17:10:19.539 [CM503016]: Call(3): Attempt to reach "0408xxxxxx"<sip:firstname.lastname@example.org> failed. Reason: No Answer 17:10:19.539 [CM503003]: Call(3): Call to sip:email@example.com:5060 has failed; Cause: 408 Request Timeout; internal 17:10:06.427 Active calls counted toward license limit:  17:09:47.402 [CM503025]: Call(3): Calling VoIPline:0408xxxxxx@(Ln.10008@MyNetFone Trunk)@[Dev:sip:firstname.lastname@example.org:5060] 17:09:47.402 [MS210002] C:3.2:Offer provided. Connection(transcoding mode): 192.168.2.1:7008(7009) 17:09:47.012 [CM503004]: Call(3): Route 1: VoIPline:0408xxxxxx@(Ln.10008@MyNetFone Trunk)@[Dev:sip:email@example.com:5060] 17:09:47.012 [CM503010]: Making route(s) to "0408xxxxxx"<sip:firstname.lastname@example.org> 17:09:47.012 [MS210000] C:3.1:Offer received. RTP connection: 192.168.2.151:16436(16437) 17:09:47.012 Remote SDP is set for legC:3.1 17:09:47.012 [CM505001]: Ext.100: Device info: Device Identified: [Man: Cisco;Mod: SPA Series;Rev: General] Capabilities:[reinvite, replaces, unable-no-sdp, no-recvonly] UserAgent: [Cisco/SPA525G-7.4.3] PBX contact: [sip:email@example.com:5060] 17:09:46.997 [CM503001]: Call(3): Incoming call from Ext.100 to "0408xxxxxx"<sip:firstname.lastname@example.org> 17:09:46.997 [CM500002]: Info on incoming INVITE: INVITE sip:email@example.com:5060 SIP/2.0 Via: SIP/2.0/UDP 192.168.2.151:5060;branch=z9hG4bK-fd6e410f Max-Forwards: 70 Contact: "Reception"<sip:firstname.lastname@example.org:5060> To: "0408xxxxxx"<sip:email@example.com> From: "Reception"<sip:firstname.lastname@example.org>;tag=910e7036de7c5b5bo0 Call-ID: email@example.com CSeq: 102 INVITE Expires: 240 Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER, UPDATE Proxy-Authorization: Digest username="100",realm="3CXPhoneSystem",nonce="414d535c01ccc0ba13:c3dd986539e1d597dcd713b23856689d",uri="sip:firstname.lastname@example.org:5060",algorithm=MD5,response="6a4ca5239cf3701a0d802e1fc52e704b" Supported: replaces User-Agent: Cisco/SPA525G-7.4.3 Content-Length: 0 edit: I ran firewall checker and it failed on Phase 2a: <18:11:26>: UDP SIP Port is set to 5060. NO RESPONSE received. Phase 2a check FAILED. Application exit code is -2 I did the unthinkable and created a PPPoE connection from windows direct to the bridged modem without a firewall running, and it still gave the same error.