Hello, I haven't analyzed your message too much now -- just wanted to ask if you looked at uac module for uacreg feature and if that is suiting or not your needs?
Cheers, Daniel On 05/05/16 14:40, Code Developer wrote: > Hello, > > I'm after some help on third-party SIP registration in Kamailio - > specifically, how to perform registration of user agents that don't > register themselves, but only send out occasional messages. The > UAs not registering themselves are devices on a GSM network that try > to save band-width by not sending REGISTER requests for themselves. > They only ever send out SIP messages when necessary, to which they > expect a reply message from our processing server. > > (Note, details like external IP addresses have been changed for security.) > > The configuration is as follows. We have a SIP server running Kamailio > (4.3, location db enabled, nathelper enabled) on a static external IP > address (50.170.158.149), a processing server on an internal network > registered with the SIP server (let's say with a User agent name of > '1000'), and a monitoring device in another part of the country > connected to the internet via a GSM network (let's say User agent name > of '2000'). The device is effectively NAT'd on the GSM provider's > private network. > > At some point the device (UA 2000) sends a SIP message to the > processing server via Kamailio (to sip:1000@50.170.158.149). The > processing server is registered, so the SIP server knows where it is > and forwards the message accordingly. 200/OK replies propagate back > successfully to the device. > > The message flow appear as below. Only relevant header fields are shown: > > Message received by the SIP server from remote device: > ======== > IP Src:60.250.149.198, Dst:50.170.158.149 > UDP Src Port: 59177, Dst Port: 5060 > -- > Request-Line: MESSAGE sip:1000@50.170.158.149 > Via: SIP/2.0/UDP 10.92.240.131:5060;branch=z9hG4bK... > To: <sip:1000@50.170.158.149> > From: <sip:2000@10.92.240.131>;tag=7a82c48a > ======== > > > Message forwarded from SIP server, received by processing server as shown: > ======== > IP Src:50.170.158.149, Dst: 192.168.0.235 > UDP Src Port:5060, Dst Port:5060 > -- > Request-Line: MESSAGE sip:1000@50.170.158.146:5060; ob SIP/2.0 > Via: SIP/2.0/UDP 50.170.158.149;branch=z9hG... > Via: SIP/2.0/UDP > 10.92.240.131:5060;rport=59177;received=60.250.149.198;branch=z9hG... > To: <sip:1000@50.170.158.149> > From: <sip:2000@10.92.240.131>;tag=7a82c48a > ======== > > > The processing server now needs to send back a reply message to the > remote, unregistered device which is NATd on the GSM internal network. > We can do this by sending back a reply to the external IP address and > rport values found in the second Via header of the message received by > the processing server (60.250.149.198, port 59177). The reply can only > be sent from the SIP server or the GSM network's router will ignore it > - it's only a temporary reply address/port open for a minute or so as > it's effectively just a NAT route to the internet. > > In the first instance, when the processing server attempts to send > back a message to the remote device via the SIP server, the SIP server > replies with a 404 as the remote device hasn't registered and the SIP > server has no idea where to send it. > > After looking at RFC3261 my conclusion was that we must get the > processing server to perform a third-party registration on behalf of > the remote device before we can send a reply message back to that device. > > My understanding is that to perform the third party registration I > should send a REGISTER request from our processing server to the SIP > server: > 1) Set the 'From' field to the AOR of the UA performing the > registration (which is the processing server, 1000). > 2) Set the 'To' field to the AOR of the UA being registered (i.e. the > remote device, 2000). > 3) Add a 'Contact' header field set to the IP address and port of the > remote device (from Via = 60.250.149.198 port 59177). > > > The message flow for the register is as follows (only relevant header > fields shown): > > Processing server sends a register request to the SIP Server: > ======== > Request-Line: REGISTER sip:50.170.158.149 SIP/2.0 > Via: SIP/2.0/UDP 192.168.0.235:5060;rport;branch=z9hG... > From: <sip:1000@50.170.158.149>;tag=e6e2d70... > To: <sip:2000@50.170.158.149> > Contact: <sip:2000@60.250.149.198:59177> > ======== > > SIP server responds to the processing server with a 401 unauthorized > response containing the auth header field (nonce challenge): > ======== > WWW-Authenticate: Digest realm="50.170.158.149", > nonce="VytkJ1crIvu4ekGp/M4mnRlYmJRciF3N" > ======== > > Processing server sends a revised register request to the SIP Server, > augmented with the authorisation header for the supplied nonce: > ======== > Request-Line: REGISTER sip:50.170.158.149 SIP/2.0 > Via: SIP/2.0/UDP 50.170.158.146:1096; rport;branch=z9hG4... > From: <sip:1000@50.170.158.149>;tag=dae68a... > To: <sip:2000@50.170.158.149> > Contact: <sip:2000@60.250.149.198:59177> > Authorization: Digest username="1000", realm="50.170.158.149", > nonce="VytkJ1crIvu4ekGp/M4mnRlYmJRciF3N" response="d4d7ffba8..." > ======== > > However, the SIP Server again responds with a 401 and won't perform > the third-party registration. I haven't been able to determine why. I > *think* the response hash the processing server is sending back is > correct. I'm using PJSIP on our processing server to perform all SIP > functionality. The processing server does obviously register > itself, the difference being that the To and From fields are the same > (<sip:1000@50.170.158.149>) and there is no Contact header. > > I'm at the point now of being unable to find any information or > examples on how third-party registration requests should be performed > - apart from RFC3261, which doesn't really describe the process very well. > > Can anyone tell me why the third-party registration would fail, > despite replying with the authorisation header? Does Kamailio first > need to be configured to allow third-party reg somehow? Alternatively, > should I be attempting to send back SIP messages to unregistered > devices in some other fashion? > > I hope someone can help or point me in the right direction. > > As an aside, when the device (UA2000) is plugged into a network via > ethernet, it does then perform its own registration and everything > works - messages go back and forth without issue. > > > _______________________________________________ > SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list > sr-users@lists.sip-router.org > http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users -- Daniel-Constantin Mierla http://www.asipto.com http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda Kamailio World Conference, Berlin, May 18-20, 2016 - http://www.kamailioworld.com
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