Fix Sdp Error - sr-users

4 Dec 2020


      Hello,
I noticed that when i do calls behind NAT i'm getting this error when i
call fix_nated_sdp() :
"nathelper [nathelper.c:1659]: replace_sdp_ip(): can't extract 'a=rtcp'
IP from the SDP"
As far as i can see, all the ips on SDP are correctly replaced to a public
IP, so i don't understand the origin of this error.
This is the SDP received by Kamailio :
Session Description Protocol
    Session Description Protocol Version (v): 0
    Owner/Creator, Session Id (o): - 3421914885 1 IN IP4 192.168.24.89
    Session Name (s): SIPPER for PhonerLite
    Connection Information (c): IN IP4 192.168.24.89
    Time Description, active time (t): 0 0
    Media Description, name and address (m): audio 5062 RTP/AVP 107 8 0 2 3
97 110 111 9 18 11 118 101
    Media Attribute (a): rtpmap:107 opus/48000/2
    Media Attribute (a): rtpmap:8 PCMA/8000
    Media Attribute (a): rtpmap:0 PCMU/8000
    Media Attribute (a): rtpmap:2 G726-32/8000
    Media Attribute (a): rtpmap:3 GSM/8000
    Media Attribute (a): rtpmap:97 iLBC/8000
    Media Attribute (a): rtpmap:110 speex/8000
    Media Attribute (a): rtpmap:111 speex/16000
    Media Attribute (a): rtpmap:9 G722/8000
    Media Attribute (a): rtpmap:18 G729/8000
    Media Attribute (a): fmtp:18 annexb=yes
    Media Attribute (a): rtpmap:11 L16/44100
    Media Attribute (a): rtpmap:118 L16/16000
    Media Attribute (a): rtpmap:101 telephone-event/8000
    Media Attribute (a): fmtp:101 0-16
    Media Attribute (a): ssrc:2716178988
    Media Attribute (a): sendrecv
And this is the SDP sent by Kamailio after NAT being treated :
Session Description Protocol
    Session Description Protocol Version (v): 0
    Owner/Creator, Session Id (o): - 3421914885 1 IN IP4 1.1.1.1 (Public IP)
    Session Name (s): SIPPER for PhonerLite
    Connection Information (c): IN IP4 1.1.1.1 (Public IP)
    Time Description, active time (t): 0 0
    Media Description, name and address (m): audio 5062 RTP/AVP 107 8 0 2 3
97 110 111 9 18 11 118 101
    Media Attribute (a): rtpmap:107 opus/48000/2
    Media Attribute (a): rtpmap:8 PCMA/8000
    Media Attribute (a): rtpmap:0 PCMU/8000
    Media Attribute (a): rtpmap:2 G726-32/8000
    Media Attribute (a): rtpmap:3 GSM/8000
    Media Attribute (a): rtpmap:97 iLBC/8000
    Media Attribute (a): rtpmap:110 speex/8000
    Media Attribute (a): rtpmap:111 speex/16000
    Media Attribute (a): rtpmap:9 G722/8000
    Media Attribute (a): rtpmap:18 G729/8000
    Media Attribute (a): fmtp:18 annexb=yes
    Media Attribute (a): rtpmap:11 L16/44100
    Media Attribute (a): rtpmap:118 L16/16000
    Media Attribute (a): rtpmap:101 telephone-event/8000
    Media Attribute (a): fmtp:101 0-16
    Media Attribute (a): ssrc:2716178988
    Media Attribute (a): sendrecv
    Media Attribute (a): oldmediaip:192.168.24.89
    Media Attribute (a): oldmediaip:192.168.24.89
Is there something failing in the SDP fix?
Best Regards,