We are trying to relay a fax from one T.38 compatible device to another. At an early stage, while we are still in PCMA, we receive a [INCOMPATIBLE_DESTINATION] This wonders, as Freeswitch should not be really involved in Codec negociation with the endpoints. In the logs below I can see, that DTMF SDP lines are handled as soon as early media is received from the target endpoint (Asterisk): 2014-02-06 21:46:26.309091 [DEBUG] switch_core_media.c:3085 Set telephone-event payload to 101 2014-02-06 21:46:26.309091 [DEBUG] switch_core_media.c:3382 Set 2833 dtmf send payload to 101 And then there is the INCOMPATIBLE_DESTINATION nua.c:879 nua_respond() nua: nua_respond: entering nua_stack.c:529 nua_signal() nua(0x1645df0): sent signal r_respond 2014-02-06 21:46:26.309091 [NOTICE] sofia.c:6051 Hangup sofia/external/49712345@30.30.30.30 [CS_CONSUME_MEDIA] [INCOMPATIBLE_DESTINATION] nua_stack.c:573 nua_stack_signal() nua(0x1645df0): recv signal r_respond 488 Not Acceptable Here nua_stack.c:271 nua_stack_event() nua(0x1645df0): event i_error 500 Responding to a Non-Existing Request So my question is: Is proxy-media broken here? Do I need another (updated Freeswitch) where this is already solved? Freeswitch is from GIT mid dec 2013. The dialplan is (in short) as follows <action data="proxy_media=true" application="set" /> <action data="sofia/gateway/provider/49712345@30.30.30.30" application="bridge" /> SDP are as follows Sender v=0 o=FreeSWITCH 1391701261 1391701262 IN IP4 10.10.10.10 s=FreeSWITCH c=IN IP4 10.10.10.10 t=0 0 m=audio 12816 RTP/AVP 8 101 13 a=rtpmap:8 PCMA/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ptime:20 Freeswitch SDP v=0 o=FreeSWITCH 0325869010 0325869011 IN IP4 20.20.20.20 s=FreeSWITCH c=IN IP4 20.20.20.20 t=0 0 m=audio 19068 RTP/AVP 8 101 13 a=rtpmap:8 PCMA/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ptime:20 Receiver's SDP v=0 o=root 458337462 458337462 IN IP4 30.30.30.31 s=Asterisk PBX 11.0.1 c=IN IP4 30.30.30.31 t=0 0 m=audio 10262 RTP/AVP 8 101 a=rtpmap:8 PCMA/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=silenceSupp:off - - - - a=ptime:20 ================= Freeswitch LOG ==================================== recv 868 bytes from udp/[30.30.30.30]:5060 at 20:46:26.309161: ------------------------------------------------------------------------ SIP/2.0 183 Session Progress Via: SIP/2.0/UDP 20.20.20.20:5080;received=20.20.20.20;rport=5080;branch=z9hG4bKXQeZgU1337FFe Record-Route: <sip:30.30.30.30;lr> From: "Telefaks" <sip:49691234567@20.20.20.20>;tag=myacymU8arjje To: <sip:49712345@30.30.30.30>;tag=as25c99f07 Call-ID: 967f3f6c-0a12-1232-a6a1-439bc1c9be81 CSeq: 55523729 INVITE Server: Asterisk PBX 11.0.1 Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH Supported: replaces, timer Contact: <sip:49712345@30.30.30.31:5060> Content-Type: application/sdp Content-Length: 264 v=0 o=root 2049304398 2049304398 IN IP4 30.30.30.31 s=Asterisk PBX 11.0.1 c=IN IP4 30.30.30.31 t=0 0 m=audio 18798 RTP/AVP 8 101 a=rtpmap:8 PCMA/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=silenceSupp:off - - - - a=ptime:20 a=sendrecv ------------------------------------------------------------------------ tport.c:3028 tport_deliver() tport_deliver(0x16d4960): msg 0x7f5f5802d0f0 (868 bytes) from udp/30.30.30.30:5080/sip next=(nil) nta.c:3221 agent_recv_response() nta: received 183 Session Progress for INVITE (55523729) nta.c:3284 agent_recv_response() nta: 183 Session Progress is going to a transaction tport.c:4227 tport_release() tport_release(0x16d4960): 0x7f5f5001a6e0 by 0x7f5f5811ced0 with 0x7f5f5802d0f0 (preliminary) soa.c:1171 soa_set_remote_sdp() soa_set_remote_sdp(static::0x7f5f6020dea0, (nil), 0x7f5f58123d6c, 264) called soa.c:1595 soa_process_answer() soa_process_answer(static::0x7f5f6020dea0) called soa_static.c:1137 offer_answer_step() soa_static_offer_answer_action(0x7f5f6020dea0, soa_process_answer): called soa_static.c:1020 soa_sdp_mode_set() soa_sdp_mode_set(0x7f5f5001adb0, 0x7f5f581285e0, ""): called soa_static.c:1283 offer_answer_step() soa_static(0x7f5f6020dea0, soa_process_answer): upgrade codecs with remote description soa.c:1730 soa_activate() soa_activate(static::0x7f5f6020dea0, (nil)) called nua_session.c:988 nua_session_client_response() nua(0x1645df0): INVITE: processed SDP answer in 183 Session Progress nua_stack.c:271 nua_stack_event() nua(0x1645df0): event r_invite 183 Session Progress nua_session.c:4137 signal_call_state_change() nua(0x1645df0): call state changed: calling -> proceeding, received answer soa.c:1098 soa_get_remote_sdp() soa_get_remote_sdp(static::0x7f5f6020dea0, [0x7f5f65afb2f8], [0x7f5f65afb2f0], [(nil)]) called soa.c:616 soa_get_params() soa_get_params(static::0x7f5f6020dea0, ...) called nua_stack.c:271 nua_stack_event() nua(0x1645df0): event i_state 183 Session Progress nua_stack.c:359 nua_application_event() nua: nua_application_event: entering 2014-02-06 21:46:26.309091 [DEBUG] switch_core_session.c:1048 Send signal sofia/external/49712345@30.30.30.30 [BREAK] 2014-02-06 21:46:26.309091 [ALERT] switch_core_state_machine.c:585 sofia/external/49712345@30.30.30.30 session thread wake state: CS_CONSUME_MEDIA! nua_stack.c:359 nua_application_event() nua: nua_application_event: entering 2014-02-06 21:46:26.309091 [DEBUG] switch_core_session.c:1048 Send signal sofia/external/49712345@30.30.30.30 [BREAK] nua.c:366 nua_handle_magic() nua: nua_handle_magic: entering 2014-02-06 21:46:26.309091 [ALERT] switch_core_media.c:286 Looking for zrtp-hash 2014-02-06 21:46:26.309091 [ALERT] switch_core_media.c:241 Deciding whether to pass zrtp-hash between legs 2014-02-06 21:46:26.309091 [ALERT] switch_core_media.c:243 CF_ZRTP_PASSTHRU_REQ not set, so not propagating zrtp-hash 2014-02-06 21:46:26.309091 [ALERT] sofia.c:983 sofia/external/49712345@30.30.30.30 Same Callee ID "Outbound Call" <49712345> nua.c:366 nua_handle_magic() nua: nua_handle_magic: entering nua.c:366 nua_handle_magic() nua: nua_handle_magic: entering 2014-02-06 21:46:26.309091 [DEBUG] sofia.c:5889 Channel sofia/external/49712345@30.30.30.30 entering state [proceeding][183] 2014-02-06 21:46:26.309091 [DEBUG] sofia.c:5899 Remote SDP: v=0 o=root 2049304398 2049304398 IN IP4 30.30.30.31 s=Asterisk PBX 11.0.1 c=IN IP4 30.30.30.31 t=0 0 m=audio 18798 RTP/AVP 8 101 a=rtpmap:8 PCMA/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=silenceSupp:off - - - - a=ptime:20 2014-02-06 21:46:26.309091 [ALERT] switch_core_media.c:286 Looking for zrtp-hash 2014-02-06 21:46:26.309091 [ALERT] switch_core_media.c:241 Deciding whether to pass zrtp-hash between legs 2014-02-06 21:46:26.309091 [ALERT] switch_core_media.c:243 CF_ZRTP_PASSTHRU_REQ not set, so not propagating zrtp-hash 2014-02-06 21:46:26.309091 [DEBUG] switch_core_media.c:3085 Set telephone-event payload to 101 2014-02-06 21:46:26.309091 [DEBUG] switch_core_media.c:3382 Set 2833 dtmf send payload to 101 nua.c:879 nua_respond() nua: nua_respond: entering nua_stack.c:529 nua_signal() nua(0x1645df0): sent signal r_respond 2014-02-06 21:46:26.309091 [NOTICE] sofia.c:6051 Hangup sofia/external/49712345@30.30.30.30 [CS_CONSUME_MEDIA] [INCOMPATIBLE_DESTINATION] nua_stack.c:573 nua_stack_signal() nua(0x1645df0): recv signal r_respond 488 Not Acceptable Here nua_stack.c:271 nua_stack_event() nua(0x1645df0): event i_error 500 Responding to a Non-Existing Request nua_stack.c:359 nua_application_event() nua: nua_application_event: entering -- With kind regards Peter Steinbach