sundance-communications.com/forum Forums Other TDM Phone Systems Sprint - Tadiran Telephones & Systems SIP Terminal Grandstream HT-502 problem on IPXoffice

The Sentinel isn't needed if on the same net. It is used as a proxy to translate external addresses to internal addresses. Especially if the phones are coming from the same external address. Sentinel will assign those different internal addresses so the UGW can sort out who is who. The 2427 (MGCP) and the 5060 (SIP) ports are control signaling. The Audio is in the RTP packets, 16400 thru 16700 for MGCP negotiated with SIP.

Sorry, meant to add. If the call is established, the control ports are working. If you then have one way audio, the RTP packet are not making it from one side to the other both ways, just one. Wireshark allows you to check up and down the line to see where they drop out.

Thanks Riman and Reataylor,
My main office and branch use Checkpoint Firewall on each site and connected through Site to Site VPN Tunel. Main office has internal IP 192.168.200.x and branch has 192.168.2.x . I just sending new ATA box (SPA2100) and I'll let you know also the wireshark data capture.