Zyxel P-2602HW-D3A crashes when used with 3CX PBX

[MrKoen]

I have a remote location with a Zyxel P-2602HW-D3A ADSL modem (the one shipped with Telfort ADSL Internet in The Netherlands). It includes VOIP capabilities. When used in conjunction with the Telfort Telefoniedienst VOIP, it works fine. When used in conjunction with a 3CX PBX installation, the modem will crash and reboot after approximately 40 seconds of having a perfect open voice connection through VOIP. It happens each and every time I try it. It will register with 3CX without any problems, just when making a call it goes wrong. The modem will completely turn off (all lights go out) and reboot. After approximately one minute the modem has been rebooted and the connection is back up. Same thing happens when I place a call again. I can't figure out why it doesn't "like" communicating with 3CX PBX but it does with Telfort Voip.

Probably a long shot, but has anybody else encountered these problems with this particular device or perhaps similar problems with another device and knows a possible solution?

 

[leejor]

If this is a router with built in VoIP,i.e., you plug a phone or two into the back of it, then you may have to disable that feature to use it with 3CX. The Modem/router/ATA will probably attempt to "intercept" any VoIP packets before they could reach 3CX behind it.

 

[MrKoen]

It indeed is a device which has Voip/Routing/Wireless/Adsl modem functionality in one. It is thereby placed directly on the ADSL internet connection. There is no firewall/router that lies in between of this device and the internet connection as provided by the ISP. I don't understand what you mean by disabling the ATA ports on the device. Thay way I won't be able to use the Voip capabilities for sure. I am using this all-in-one device to connect my POTS phone to 3CX through VoIP. The strange thing is that it DOES connect to 3CX. It DOES register itself perfectly. The connection DOES show up as being "green" thus connected in the 3CX Management view. It even DOES make a vocal connection to any destination. Only after approximately 40 seconds (give or take 10 seconds) the all-in-one modem will crash and reboot. I have also seen occurrences where it would directly crash again after rebooting and registering to 3CX, but most of the time it would register perfectly and only crash after setting up a call.

 

[leejor]

I didn't realize that you were actually using the ATA ports in the Modem/router. I assumed that you the only VoIP device you were going to use was 3CX behind the router. Have you tried running the firewall checker?

My concern with running 3CX in conjunction with another VoIP device is the "sharing" of ports. Not knowing the architecture of your router, I don't know if the built in ATA's are using a separate public IP or they share the IP (and port numbers) with the devices behind it (3CX). The common default port for VoIP is 5060, 3CX uses that, and one of the ATA devices may as well.
Did you follow something like this? http://portforward.com/english/routers/port_forwarding/ZyXEL/P-2602HW-D3A/3CX.htm

It could turn out to be a hardware fault. If you have a record of all of your settings, as a last resort, you could try a "factory" reset, if that option is available, and start over. There could be some corruption in the data of the unit that causes the crashes.

Are you running the latest firmware?

 

[MrKoen]

leejor, thanks for providing your thoughts again. I just ran the firewall checker again to make sure all ports can be reached. All seems fine with that:

3CX Firewall Checker, v1.0. Copyright (C) 3CX Ltd. All rights reserved.

<17:07:00>: Phase 1, checking servers connection, please wait...
<17:07:00>: Stun Checker service is reachable. Phase 1 check passed.
<17:07:00>: Phase 2a, Check Port Forwarding to UDP SIP port, please wait...
<17:07:05>: UDP SIP Port is set to 5060. Response received correctly with no translation. Phase 2a check passed.

<17:07:05>: Phase 2b. Check Port Forwarding to TCP SIP port, please wait...
<17:07:10>: TCP SIP Port is set to 5060. Response received correctly with no translation. Phase 2b check passed.

<17:07:10>: Phase 3. Check Port Forwarding to TCP Tunnel port, please wait...
<17:07:14>: TCP TUNNEL Port is set to 5090. Response received correctly with no translation. Phase 3 check passed.

<17:07:14>: Phase 4. Check Port Forwarding to RTP external port range, please wait...
<17:07:20>: UDP RTP Port 9000. Response received correctly with no translation. Phase 4-01 check passed.
<17:07:24>: UDP RTP Port 9001. Response received correctly with no translation. Phase 4-02 check passed.
... removed for readability (all passed) ...
<17:11:01>: UDP RTP Port 9049. Response received correctly with no translation. Phase 4-50 check passed.
<17:11:05>: UDP RTP Port 9050. Response received correctly with no translation. Phase 4-51 check passed.

Application exit code is 0

To draw an idea of the setup of the 3CX installation I'm running:

- The 3CX server is equipped with two NICs. One facing the internal network and one being directly bound to the internet through a public IPv4 and public IPv6 address. It uses the standard Windows firewall to only allow communication through the 3CX ports from the internet.
- One remote network connects via a permanent VPN connection over IPv6 using Linksys SPA3102 and Linksys PAP2T devices to the internal network on which the 3CX server resides. These devices have private IPv4 addresses and use the internal IPv4 address of the 3CX server to communicate with it using the IPv4 protocol.
- The extension causing trouble is located remotely from the 3CX server on a home ADSL connection with a fixed IPv4 address. It connects directly through the internet using IPv4, without a VPN, to the internet facing NIC of the 3CX server.

I have not opened up any ports on the firewall of the Zyxel device. I assumed since it is also the ADSL modem/firewall it will place it's VoIP capabilities outside of its own firewall. I confirmed this assumption for myself by also not having to open any ports to use the VoIP service delivered by the ISP of the ADSL connection and by being able to register and open a vocal contact with the 3CX server.

The firmware is the latest, although it dates back from August 2008, there is no newer firmware available unfortunately.

I have also tried a factory reset. As the matter of fact, it occurred to me once that the device got into a reboot loop because after rebooting it would register with 3CX, directly crash and reboot again, register, crash and reboot again, etc. The only way to stop this from happening was by disconnecting the DSL line, having the device boot up, factory reset and plug back in the DSL line. So no avail through this method.

I think we can point it down to being an error in Zyxels firmware. Strange thing is that it never occurs with the VoIP of the ISP though. So 3CX must send out some unique command which causes the Zyxel to crash immediately. I will try to see if I can get Zyxel to analyze the situation, but I guess they won't. I'll try to get my hands on another Linksys PAP2T or SPA3102 to see if that will work in this setup.

If any more thoughts or ideas come up, please do let me know.

Thanks!

 

[SY]

Hi Koen,

3CX PBX is not designed to detect problems in other sortware/hardware, but it looks like we, accidentally, triggered a very bad bug in Zyxel P-2602HW-D3A firmware. All requests, sent by 3CX PBX, are "wellformed". If Zyxel doesn't undestand it then it can reject request at any time.
I think that you have to report this issue to Zyxel.

Most probably it is not the problem of Zyxel device and it is the problem of "customization" of the device made by the provider.

Thanks

 

[MrKoen]

Hi Stepan,

I have sent Zyxel support an e-mail regarding this issue. Perhaps they will do something with it, but my experience is that they will either not reply or reply with default "check your settings" or "contact 3CX instead, not our problem" answers. We'll see. In case something useful comes out of it, I will update this topic.

 

[SY]

Hi Stepan,

I have sent Zyxel support an e-mail regarding this issue. Perhaps they will do something with it, but my experience is that they will either not reply or reply with default "check your settings" or "contact 3CX instead, not our problem" answers. We'll see. In case something useful comes out of it, I will update this topic.

I've extended my post with following sentence:

Most probably it is not the problem of Zyxel device and it is the problem of "customization" of the device made by the provider.

 

[MrKoen]

Just got a response from Zyxel. Guess what their response was. "It is caused by the 3CX installation, not by our device". Yay! :cry: Well.. at least they took the 5 seconds to reply.. :|

The Zyxel device doesn't look to be customized too much by ISP Telfort. Just that the proper settings are there by default after a factory reset. There isn't much to configure in the VoIP part of the device anyway. Guess this is a hopeless case as expected. I will try a Linksys PAP2T device instead, but I saw that can be quite a challenge to use when it is placed behind NAT, which is the only option I have for that location.

 

[SY]

Just got a response from Zyxel. Guess what their response was. "It is caused by the 3CX installation, not by our device". Yay! :cry: Well.. at least they took the 5 seconds to reply.. :|

The Zyxel device doesn't look to be customized too much by ISP Telfort. Just that the proper settings are there by default after a factory reset. There isn't much to configure in the VoIP part of the device anyway. Guess this is a hopeless case as expected. I will try a Linksys PAP2T device instead, but I saw that can be quite a challenge to use when it is placed behind NAT, which is the only option I have for that location.

Firewall/network gateway/NAT device which is designed to manage (and PROTECT!) bridge between local and external network but can be rebooted by one UDP packet... It is kind of a "nonsence", isn't it?

I have no comments...

Thanks

 

[MrKoen]

My point exactly Stepan. Take another guess what the answer from Zyxel was earlier today when I pointed exactly that out to them and offered them cooperation to resolve the issue. They replied with that I could file a RMA for the device, but that they would only test it in a normal (what's normal? The ideal environment?) situation and that I would have to pay research costs if they would not be able to find any problems during their test in their own lab.

Zyxel.. for all your network security (not) :shock:

 

[victoriaw]

Any news on this subject? What did the Zyxel people answered, after almost a year?

 

[MrKoen]

Nope, nothing. I didn't want to take the risk to send the device to them and have them say it works in what they consider a normal environment so I would have to pay for the research. I switched the ISP to Alice and used a Linksys SPA3102 instead.