I'm experiencing a difficulty which I think it could be related to a bug, but still have no idea how to pin point it. any comment is appreciated. The issue is as below
I have a L2TP tunnel on my router to another network. there is an IP PBX in the second network. my iPhone using Acrobits Groundwire connects to the IP PBX. i.e. my router does the NAT and route the traffic to L2TP tunnel.
sometime I found my groundwire can not register in the IP PBX (SIP)
usually with restarting the router the problem got solved.
recently I realized that if I delete the existing NAT connection from connection table, it would get resolved!
I realized that when the issue is there, the sate of the connection is Cs (Confirmed, srcnat)
but after deleting, it turns into "SACs" (seen reply, assured, confirmed, srcnat)
any comment on how to troubleshoot it?
still I'm not able to reproduce it. but it happens frequently