I have set-up two Grandstream phones, one is inside my LAN and one is outside. Below is the ngrep output. Can you please explain me both (openserctl ul show and ngrep) and where the problem my be? 7111 calls 7211, both are registerd as: ...Record(0x2b68516ca938)... domain: 'location' aor : '7111' ~~~Contact(0x2b68516ca9b0)~~~ domain : 'location' aor : '7111' Contact : 'sip:7111@192.168.250.115' Expires : 404 q : Call-ID : &#39;748276c266577824(a)192.168.250.115&#39; CSeq : 10157 User-Agent: 'Grandstream GXV3000 1.0.0.24' received : '' Path : '' State : CS_NEW Flags : 0 Sock : 192.168.250.41:5060 (0x610fc0) Methods : 7807 next : (nil) prev : (nil) ~~~/Contact~~~~ .../Record... ...Record(0x2b68516d0950)... domain: 'location' aor : '7211' ~~~Contact(0x2b68516cb7d0)~~~ domain : 'location' aor : '7211' Contact : 'sip:7211@192.168.87.103' Expires : 2382 q : Call-ID : &#39;8d96c35345b355d7(a)192.168.87.103&#39; CSeq : 10001 User-Agent: 'Grandstream GXV3000 1.0.0.24' received : '' Path : '' State : CS_NEW Flags : 0 Sock : 59.124.210.41:5060 (0x610ef0) Methods : 7807 next : (nil) prev : (nil) ~~~/Contact~~~~ .../Record... # U 2006/09/26 10:49:27.574906 192.168.250.115:5060 -> 192.168.250.41:5060 INVITE sip:7211@192.168.250.41 SIP/2.0. Via: SIP/2.0/UDP 192.168.250.115;branch=z9hG4bKf777932528b49881. From: <sip:7111@192.168.250.41>;tag=d71217459a54cde3. To: <sip:7211@192.168.250.41>. Contact: <sip:7111@192.168.250.115>. Supported: replaces, timer. Call-ID: 76740d0122a46445(a)192.168.250.115. CSeq: 15245 INVITE. User-Agent: Grandstream GXV3000 1.0.0.24. Max-Forwards: 70. Allow: INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE,UPDATE,PRACK. Content-Type: application/sdp. Content-Length: 438. . v=0. o=7111 8000 8000 IN IP4 192.168.250.115. s=SIP Call. c=IN IP4 192.168.250.115. t=0 0. m=audio 15004 RTP/AVP 0 3 18 4 8. a=sendrecv. a=rtpmap:0 PCMU/8000. a=rtpmap:3 GSM/8000. a=rtpmap:18 G729/8000. a=rtpmap:4 G723/8000. a=rtpmap:8 PCMA/8000. a=ptime:20. m=video 15006 RTP/AVP 99. a=sendrecv. a=rtpmap:99 H264/90000. a=fmtp:99 profile-level-id=42801E; packetization-mode=0; sprop-parameter-sets=J0KAFJWgUH5A,KM4C/ID=. a=framerate:15. # U 2006/09/26 10:49:27.587708 192.168.250.41:5060 -> 192.168.250.115:5060 SIP/2.0 100 trying -- your call is important to us. Via: SIP/2.0/UDP 192.168.250.115;branch=z9hG4bKf777932528b49881. From: <sip:7111@192.168.250.41>;tag=d71217459a54cde3. To: <sip:7211@192.168.250.41>. Call-ID: 76740d0122a46445(a)192.168.250.115. CSeq: 15245 INVITE. Server: OpenSer (1.1.0-notls (x86_64/linux)). Content-Length: 0. Warning: 392 192.168.250.41:5060 "Noisy feedback tells: pid=31770 req_src_ip=192.168.250.115 req_src_port=5060 in_uri=sip:7211@192.168.250.41 out_uri=sip:7211@192.168.87.103 via_cnt==1". . # U 2006/09/26 10:49:56.862266 192.168.250.41:5060 -> 192.168.250.115:5060 SIP/2.0 408 Request Timeout. Via: SIP/2.0/UDP 192.168.250.115;branch=z9hG4bKf777932528b49881. From: <sip:7111@192.168.250.41>;tag=d71217459a54cde3. To: <sip:7211@192.168.250.41>;tag=fa997f81440371de71ab448ebdb9af56-37d0. Call-ID: 76740d0122a46445(a)192.168.250.115. CSeq: 15245 INVITE. Server: OpenSer (1.1.0-notls (x86_64/linux)). Content-Length: 0. Warning: 392 192.168.250.41:5060 "Noisy feedback tells: pid=31771 req_src_ip=192.168.250.115 req_src_port=5060 in_uri=sip:7211@192.168.250.41 out_uri=sip:7211@192.168.87.103 via_cnt==0". . # U 2006/09/26 10:49:56.865291 192.168.250.115:5060 -> 192.168.250.41:5060 ACK sip:7211@192.168.250.41 SIP/2.0. Via: SIP/2.0/UDP 192.168.250.115;branch=z9hG4bKf777932528b49881. From: <sip:7111@192.168.250.41>;tag=d71217459a54cde3. To: <sip:7211@192.168.250.41>;tag=fa997f81440371de71ab448ebdb9af56-37d0. Contact: <sip:7111@192.168.250.115>. Call-ID: 76740d0122a46445(a)192.168.250.115. CSeq: 15245 ACK. User-Agent: Grandstream GXV3000 1.0.0.24. Max-Forwards: 70. Allow: INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE,UPDATE,PRACK. Content-Length: 0. . #