HI,
Even we observed in Wireshark traces, no username is included in REGISTER request. Any changes required? No, we are not using NATURAL in our platform.
The "NATURAL" has been an automatic spell checking of my tablet. It should have been "NAT".
Observed there is no communication between PCSCF – ICSCF while registration and also attaching the tracefile(tcpdump) using command “tcpdump -i any -s 3000 -w /var/tmp/trace_OpenIMS.pcap not port 22 and not port 3306”.
As you can see in the trace: The P-CSCF forwards the REGISTER request to 10.0.0.9 which is not the I-CSCF (and not prepared to receive such messages). You should check the forwarding to I-CSCF in kamailio-pcscf.cfg.
Next time you should start with the trace also at startup of the x-CSCF to see that the Diameter connections are up and running.
BR Franz