Hi, I m using mediaproxy for nat raversal and rtp handling. Nat is working fine. Clients behind the nat are connected after ringing, but no audo transmission takes place in either side. On running the sessions.py of mediaproxy, the output is as following, [root@sip ser]# python /usr/local/mediaproxy/sessions.py Caller Via Called Status Duration Codec Type Traffic ---------------------------------------------------------------------------- --------------------------- 61.16.236.34:24742 - 66.114.236.182:35012 - ?.?.?.?:? inactive 0'12" G711u Audio 19.42k/704/480 Total traffic: 0bps/0bps/0bps (in1/in2/out) Session count: 1 Proxy version: 1.4.2 --------------- Why is the Called filed showing a ?.?.?.? even though the client is fully resolved. Please help urgent!!! Regards, Ashutosh Kumar Chetu, Inc. Ph : 1(305) 402 6724 - Witin US Ph : 91 120 5323340 - Outside US Fax:1 (305) 832 5987 For more  information, please visit http://www.chetu.com