There are many threads in this forum on how to change settings not meant to be changed by the user. I suddenly find that the phone is using such information which I have not entered. It seems that those settings have been entered/fetched from an operator without my knowledge. Should this be possible for an operator the implications are most interesting and I would appreciate comments:
I was loosing registration when using the operator Sipgate with my E61. The problem was caused by a function called ALG in my router. Turning of the ALGs solved the problem and it works excellent now. When debugging I sniffed the traffic from the Internet to the router. A registration process started with a request to REGISTER from the E61, after a successful registration nothing happened until the lease time had expired and the E61 should register again. After solving the problem with the router it continued like this.
It still works excellent but yesterday I noticed from the light emitting diodes on the router that there was a frequent traffic from the router to the E61 which had not been there before. Roughly every 15 seconds there was traffic. I sniffed the traffic between the router and the E61 and found:
- Before the actual request for REGISTRATION the E61 contacts stun1.sipgate.net and gets a prompt reply. No data in the packets which I can parse. After that registration proceeds immediately as usual.
- After that a repeated cycle starts where the E61 sends a packet to sipgate.co.uk (registrar and proxy server) and imidiately another to stun1.sipgate.net. After roughly 7 seconds the E61 gets a packet from sipgate.co.uk, after another 14 seconds another packet from sipgate.co.uk. After another 10 seconds the cycle starts again by the E61 sending packets to sipgate.co.uk and to stun1.sipgate.net again. A cycle with a period time of roughly 30 seconds. This continues until it is time for REGISTRATION again. Small UDP packets with nothing I can parse.
- From where does the E61 get the address to the stun server? I haven't entered it. As a user I can not enter it.
- What is initiating the contact with the stun server before the registration and the communication between renewals of the registration? Have I got “stun” without requesting it.