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Polson, MT

ZyXEL USG50 - IP Phones

I have searched, and searched...but have yet to find even a post about my issue, nevermind a solution.

Setup - We have a USG100 at the main office, and USG50's at each remote location; each with the latest firmware. There are VPNs established between each location and the main office, and those seem to be rock solid. The phone system is Samsung and I am having issues with the phones at a single location. The phones talk through the VPN to connect to the phone system at the main office.

The phones will initially connect to the phone system upon restarting them (dial tone is there), but it will go silent after ~20 seconds or so and then seem to lockup before getting the message System:KP which is the phone reconnecting to the system. It did this even when the phones were going to a public address the phone system had before we placed it inside of the main network and pointed all remote phones through the VPN.

I have tried both DHCP and static addresses on the phone, and setup firewall rules allowing this phone through no matter what.

I thought it might be an issue with having too many devices on the network (I think the USG said something like 5-10) and they had 11-12 here, so I removed several of them but it still wont let this phone connect. I've replaced the phone as well.

Any ideas on what I might try next?


You mention public IP, was there a firewall/nat device in front when it also had a public IP at any of the ends, ie Phone or Central?

And there is a dial-tone, but go silent after 20 seconds. Have made a call and it dies during the conversation? Or if you just check for 20+ seconds if there is a dial-tone. Or it always dies after 20 seconds after is has registered with the server?
"Perl is executable line noise, Python is executable pseudo-code."

I hate Vogons
Burlington, ON
·TekSavvy DSL
·Bell Fibe
reply to dcsbrock
My suggestion is to get some network packet capture on the IP phone side. Start the capture when all is working then leave it on until the phone dies. Also if the phone has some debugging I'd turn it on. As well as capturing all possible logs from ZyXel and look at all the collected info at the time-stamp when the phone dies ... see what pops up.