[Spce-user] Running CE behind an SBC

[Nerijus Barauskas]

Hi,

I have a CE mr6.5.2 running inside a private network. At the network edge we have an SBC (IP YYY.YYY.YYY.YYY) which proxies the traffic between the public network and the CE server.

Phones (IP XXX.XXX.XXX.XXX) register via the SBC, which inserts a path header and forwards to CE.

Phones can make outound calls, but on inbound calls, CE ignores the path and tries to send the call difrectly to the phone's IP (XXX.XXX.XXX.XXX) present in the Contact.

What appears to be happening is that the proxy is using the path to send the request to the load balancer, but the rest of the path is being ignored.

Any hints appreciated.

Below is the outbput of proxy ul show for the phone:

# ngcp-kamctl proxy ul showphonetest at test.mydomain.com
{
   "AoR":"phonetest at test.mydomain.com",
   "Contacts": [
     {
       "Contact": {
         "Address":"sip:phonetest at XXX.XXX.XXX.XXX:7477;transport=UDP;rinstance=0478b7f3dd34e980",
         "Expires": 388,
         "Q": -1,
         "Call-ID": "GGGGdiKBxQABNklNSjpyiw..",
         "CSeq": 2,
         "User-Agent": "Zoiper rv2.9.2",
         "Received": "[not set]",
         "Path": "<sip:lb at 127.0.0.1;lr;socket=sip:ZZZ.ZZZ.ZZZ.ZZZ:5060>,<sip:YYY.YYY.YYY.YYY;lr;received=sip:XXX.XXX.XXX.XXX:7477>",
         "State": "CS_SYNC",
         "Flags": 0,
         "CFlags": 0,
         "Socket": "udp:127.0.0.1:5062",
         "Methods": 975,
         "Ruid": "uloc-5c35f1ac-1103-aa",
         "Instance": "[not set]",
         "Reg-Id": 0,
         "Server-Id": 0,
         "Tcpconn-Id": -1,
         "Keepalive": 0,
         "Last-Keepalive": 1547118521,
         "Last-Modified": 1547118521
       }
     }
   ]
}


Here is the REGISTER packet:

2019/01/10 11:08:41.546039 YYY.YYY.YYY.YYY:5060 -> ZZZ.ZZZ.ZZZ.ZZZ:5060
REGISTERsip:test.mydomain.com;transport=UDP  SIP/2.0
Via: SIP/2.0/UDP YYY.YYY.YYY.YYY;branch=z9hG4bKf8ec.1814ce53196f6e4039f3e2c7f94221dc.0
Via: SIP/2.0/UDP 100.115.92.2:41451;received=XXX.XXX.XXX.XXX;branch=z9hG4bK-524287-1---c067471c3487d2b7;rport=7477
Max-Forwards: 69
Contact:<sip:phonetest at XXX.XXX.XXX.XXX:7477;transport=UDP;rinstance=0478b7f3dd34e980>
To:<sip:phonetest at test.mydomain.com;transport=UDP>
From:<sip:phonetest at test.mydomain.com;transport=UDP>;tag=40d2244b
Call-ID: GGGGdiKBxQABNklNSjpyiw..
CSeq: 1 REGISTER
Expires: 60
Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, MESSAGE, OPTIONS, INFO, SUBSCRIBE
User-Agent: Zoiper rv2.9.2
Allow-Events: presence, kpml, talk
Content-Length: 0
Supported: path
Path:<sip:YYY.YYY.YYY.YYY;lr;received=sip:XXX.XXX.XXX.XXX:7477>

Kind Regards,
Nerijus Barauskas