Hello, I have a kamailio on SITE A using a public IP. I'm trying to setup another kamailio on SITE B with NAT.
When I try to make a call from SITE B to SITE A, the call is initiated but when comes the SDP my equipment on SITE B does not reply to SDP sent by kamailio on SITE A.
I made some test and use only Public IP between the 2 sites and it works properly. So I think that I have a problem on my NAT configuration or maybe I'm missing something. Can someone help me one this problem ? Do you have an idea on what could be blocking. Thank in advance for your help. Regards, Nathan
Can you share configuration snippets and packet capture snippets?
Perhaps including the SDP so you can show us what's missing?
Thanks
David
On Tue, Jul 15, 2025 at 10:12 AM Nathan C via sr-users < sr-users@lists.kamailio.org> wrote:
Hello, I have a kamailio on SITE A using a public IP. I'm trying to setup another kamailio on SITE B with NAT.
When I try to make a call from SITE B to SITE A, the call is initiated but when comes the SDP my equipment on SITE B does not reply to SDP sent by kamailio on SITE A.
I made some test and use only Public IP between the 2 sites and it works properly. So I think that I have a problem on my NAT configuration or maybe I'm missing something. Can someone help me one this problem ? Do you have an idea on what could be blocking. Thank in advance for your help. Regards, Nathan __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
Hello, Yes of course. Here is some details :
Kamailio config : alias="IP_PRIV_KAMAILIO_SITE_B" listen=tcp:IP_PRIV_KAMAILIO_SITE_B:5060 advertise IP_PUBLIQUE_SITE_B:5060
I also configured RTP Engine : interface = KAMAILIO_IP_PRIV_SITE_B!IP_PUBLIQUE_SITE_B listen-ng = KAMAILIO_IP_PRIV_SITE_B:2223
Here is the SDP answering from SITE A to SITE B: SIP/2.0 200 Answering Record-Route: sip:IP_PUBLIQUE_SITE_A;transport=tcp;lr;ftag=F3D17100-4B77D8CB;did=541.30f2;nat=yes Record-Route: sip:IP_PUBLIQUE_SITE_B;transport=tcp;lr;ftag=F3D17100-4B77D8CB;did=541.d551;nat=yes Via: SIP/2.0/TCP phone_site_B:5060;rport=60620;branch=z9hG4bK2D80151007ed0c01a8c0 From: "22-3283278309681.ABCDPHONEB" sip:101@KAMAILIO_IP_PRIV_SITE_B;tag=F3D17100-4B77D8CB To: sip:3283278309681.ABCD@SITE_A_DOMAIN;tag=c2daa2041dba02fd CSeq: 2 INVITE Call-ID: b553f084-90e45fef-61ca1252@phone_site_B Server: baresip v3.15.0 (x86_64/Linux) Contact: sip:phone_site_A.@IP_PUBLIQUE_SITE_A:5060;transport=tcp;alias=phone_site_A~55590~2 Allow: INVITE,ACK,BYE,CANCEL,OPTIONS,NOTIFY,INFO,MESSAGE,UPDATE,REFER Supported: gruu,replaces,norefersub Content-Type: application/sdp Content-Length: 1153
v=0 o=- 1428244366 302624626 IN IP4 IP_PUBLIC_TURN_SITE_A s=- c=IN IP4 IP_PUBLIC_TURN_SITE_A t=0 0 m=audio 41762 RTP/AVP 9 0 8 119 c=IN IP4 IP_PUBLIC_TURN_SITE_A b=AS:128 a=rtpmap:9 G722/8000 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:119 telephone-event/8000 a=fmtp:119 0-15 a=rtcp:41763 IN IP4 IP_PUBLIC_TURN_SITE_A a=sendrecv a=ssrc:322326744 cname:sip:3283278309681.ABCD@SITE_A_DOMAIN a=minptime:20 a=ptime:20 a=label:1 m=video 44252 RTP/AVP 109 110 c=IN IP4 IP_PUBLIC_TURN_SITE_A b=AS:1920 a=rtpmap:109 H264/90000 a=fmtp:109 packetization-mode=0;profile-level-id=42e01f;max-mbps=108000;max-fs=3600;max-br=2048 a=rtpmap:110 H264/90000 a=fmtp:110 packetization-mode=1;profile-level-id=42e01f;max-mbps=108000;max-fs=3600;max-br=2048 a=rtcp:44253 IN IP4 IP_PUBLIC_TURN_SITE_A a=sendrecv a=ssrc:4213384512 cname:sip:3283278309681.ABCD@SITE_A_DOMAIN a=framerate:30.00 a=rtcp-fb:* nack a=rtcp-fb:* nack pli a=content:main a=label:2 m=application 43622 UDP/BFCP * c=IN IP4 IP_PUBLIC_TURN_SITE_A a=floorctrl:c-s a=setup:actpass a=confid:1005 a=userid:6 a=floorid:1 mstrm 3 a=connection:new m=application 0 RTP/AVP 0
Hello,
Does anyone have an idea on my problem ?
Thanks in advance for your help. Regards, Nathan
Hi Nathan,
The router at {IP_PUBLIC_TURN_SITE_A} should have port 41762 forwarded to the relevant port on the SIP sevice port and IP on the local network.
m=audio 41762 RTP/AVP 9 0 8 119 c=IN IP4 IP_PUBLIC_TURN_SITE_A
check that the ephemoral port os being handle correctly. you may need to capture a pcap on the device or on a pc with sipp or a softphone to check you see the media. Also check the fire wall is not blocking the traffic. If the site B is affected then you need to check the SDP on the INVITE and again check the firewall and portworewarding is alloing the established or related traffic back in. You could also use RTPEngine to manage the NATTING and have it act as a media proxy on the edge of the B LAN
Regards,
Richard
On 01/09/2025 10:27, Nathan C via sr-users wrote:
Hello,
Does anyone have an idea on my problem ?
Thanks in advance for your help. Regards, Nathan __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions --sr-users@lists.kamailio.org To unsubscribe send an email tosr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
Hello Richard,
Thank you for your feedback. I'm gonna check this.
Abuot RTPEngine, I set it up but not seems to work. In the conf file I configure RTPEngine like this : interface = KAMAILIO_IP_PRIV_SITE_B!IP_PUBLIQUE_SITE_B listen-ng = KAMAILIO_IP_PRIV_SITE_B:2223
Do I need to add more configuration ?
Thanks a lot for your help. Regards, Nathan
Hi,
You need to configure RTPEngine to have an external interface that is at lease mapped to its private address and an internal interface on the LAN. you call one of the RTPEngine functions to get RTPEngine to handle the RPT traffic and update the SDP
I suggent you ead the relevant DOcumentation for rtpengine module and the RTPengine documentation on github.
Regards,
Richard
On 02/09/2025 13:30, Nathan C via sr-users wrote:
Hello Richard,
Thank you for your feedback. I'm gonna check this.
Abuot RTPEngine, I set it up but not seems to work. In the conf file I configure RTPEngine like this : interface = KAMAILIO_IP_PRIV_SITE_B!IP_PUBLIQUE_SITE_B listen-ng = KAMAILIO_IP_PRIV_SITE_B:2223
Do I need to add more configuration ?
Thanks a lot for your help. Regards, Nathan __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
-
David Tek -
Nathan C -
Richard Robson