Hello,

I have a strange error when proyy-media T38 faxes.
Freeswitch is behind NAT (internal 192.168.12.248, external 5.10.xxx.yyy), other, receiving Server is also a Freeswitch

A connection is made via G.711A, we hear the machines negociating, then we receive a T.38 reinvite from the remote Freeswitch server.
The local ATA 30@ reponds with T38 SDP, Freeswitch is passing it to the remote site (and there the error occurs). See error in bold:

2016-12-01 15:28:55.534228 [DEBUG] sofia.c:6937 Channel sofia/internal/30@192.168.12.248 entering state [completing][200]
2016-12-01 15:28:55.534228 [DEBUG] sofia.c:6944 Duplicate SDP
v=0
o=30 8002 8001 IN IP4 192.168.12.99
s=SIP Call
c=IN IP4 192.168.12.99
t=0 0
m=image 5012 udptl t38
a=T38FaxVersion:0
a=T38MaxBitRate:14400
a=T38FaxRateManagement:transferredTCF
a=T38FaxMaxBuffer:500
a=T38FaxMaxDatagram:500
a=T38FaxUdpEC:t38UDPRedundancy

2016-12-01 15:28:55.534228 [DEBUG] sofia.c:6937 Channel sofia/internal/30@192.168.12.248 entering state [ready][200]
2016-12-01 15:28:55.554501 [DEBUG] mod_sofia.c:2088 Responding with 200 [OK]
2016-12-01 15:28:55.554501 [DEBUG] switch_core_media.c:8955 sofia/external/0403801xxxxxxx image media sdp:
v=0
o=FreeSWITCH 1480572959 1480572961 IN IP4 5.10.xxx.yyy
s=FreeSWITCH
c=IN IP4 5.10.xxx.yyy
t=0 0
m=image 29544 udptl t38
a=T38FaxVersion:0
a=T38MaxBitRate:14400
a=T38FaxRateManagement:transferredTCF
a=T38FaxMaxBuffer:500
a=T38FaxMaxDatagram:500
a=T38FaxUdpEC:t38UDPRedundancy

2016-12-01 15:28:55.554501 [ERR] switch_rtp.c:6420 Poll failed with error: 9 [Bad file descriptor]
2016-12-01 15:28:55.554501 [DEBUG] switch_ivr_bridge.c:712 sofia/external/0403801xxxxxxx ending bridge by request from read function
2016-12-01 15:28:55.554501 [DEBUG] switch_ivr_bridge.c:785 BRIDGE THREAD DONE [sofia/external/0403801xxxxxxx]
2016-12-01 15:28:55.554501 [NOTICE] switch_ivr_bridge.c:889 Hangup sofia/external/0403801xxxxxxx [CS_EXCHANGE_MEDIA] [NORMAL_CLEAR

Some background Info:

What is the cause of this? Maybe a problem with port 29544? But port 29544 was already previously used with G.711A.

-- 
With kind regards
Peter Steinbach 

Telefaks Services GmbH
mailto:lists (att) telefaks.de
Internet: www.telefaks.de