[Kamailio-Users] ACK/BYE problem with NAT

[Dubravko Caric]

Hi all,

I have a problem when calling from UAC#1 (public IP address) to UAC#2 (private IP address), call is dropping after 30 sec. STUN and ICE are disabled in UAC#2. Other way is working OK (UAC#2 --INVITE--> UAC#1), RTPProxy is in the middle,... 

Kamailio is aware that UAC#2 is behind NAT and adds received filed on REGISTER.

MySQL location table:
contact                                                                          received     
sip:bob at 10.2.4.18:1025;rinstance=24c6e191484e570a     sip:UAC#2_PUBLIC_IP_ADDRESS:55671

Why proxy is not aware that UAC#2 is behind NAT (for BYE and ACK) when call is initiated by UAC#1 and thus sends ACK/BYE to private IP address? Shouldn't Contact header be rewriten with NAT address/port and also a "c" filed in SDP with RTPProxy address? fix_nated_contact() sholud fix contact header for transaction-starting messages like ACK and BYE...

I'm using kamailio 1.5.1-tls and standard kamailio.cfg (to be sure that I'm not using my cfg which could be faulty)...

Thanks a lot

Dubravko


INVITE: *working OK*
#
U UAC#1_PUBLIC_IP_ADDRESS:24354 -> KAMAILIO_PUBLIC_IP_ADDRESS:5958
  INVITE sip:bob at example.com SIP/2.0....

U UAC#1_PUBLIC_IP_ADDRESS:5958 -> UAC#2_PUBLIC_IP_ADDRESS:55671
  INVITE sip:bob at 10.2.4.18:1025;rinstance=24c6e191484e570a SIP/2.0..


ACK (and BYE): *not working*
#
U UAC#1_PUBLIC_IP_ADDRESS:24354 -> KAMAILIO_PUBLIC_IP_ADDRESS:5958
  ACK sip:bob at 10.2.4.18:1025;rinstance=24c6e191484e570a SIP/2.0....
#
U KAMAILIO_PUBLIC_IP_ADDRESS:5958 -> UAC#2_PRIVATE_IP_ADDRESS:1025
  ACK sip:bib at 10.2.4.18:1025;rinstance=24c6e191484e570a SIP/2.0....