NAT traversal: OpenSIPS sets c=127.0.0.1

Rita
2012-03-23
2013-05-09
  • Rita
    Rita
    2012-03-23

    Hello!

    We're now running OpenSIPS in the Amazon cloud. We see various issues with the NAT traversal. Calling from the corpnet that's behind NAT and that has a SIP ALG enabled via OpenSIPS in AWS back to the SIP UA that has public IP (no NAT).

    SIP ALG modifies Contact and c= info accordingly. Here are the values in question:

    INVITE (leaving the originator):
    Contact: <sip:6505570@10.100.120.206:5060>
    Owner/Creator, Session Id (o): TPSWAVE-SIP 2921 1 IN IP4 10.100.120.206
    Connection Information (C): IN IP4 10.100.120.206

    Incoming INVITE (as OpenSIPS receives it)
    Contact: <sip:6505570@70.103.200.226:1047>
    Owner/Creator, Session Id (o): TPSWAVE-SIP 2921 1 IN IP4 10.100.120.206
    Connection Information (C): IN IP4 70.103.200.226

    Outgoing INVITE (leaving OpenSIPS)
    Contact: <sip:6505570@70.103.200.226:1047;nat=yes>
    Owner/Creator, Session Id (o): TPSWAVE-SIP 2921 1 IN IP4 10.100.120.206
    Connection Information (C): IN IP4 127.0.0.1

    We cannot figure out why the OpenSIPS decides to insert the loopback address for "c=". It puts the loopback address whether we call fix_nated_sdp() or not.

    Can anybody please help?

    Thanks!
    Rita

     
  • Hi,

    what functions do you use for manipulating the SDP part in the INVITE - the fix_nated_sdp ? the rtpproxy or mediaproxy related functions ?

    Also, what is the address opensips is listening on (on the machine) and where the original INVITE seems to come from (as IP) from opensips perspective ?

    Regards,
    Bogdan

     
  • Rita
    Rita
    2012-03-29

    That was an rtpproxy, we started it on 127.0.0.1… Now it's all working fine. Thanks!