IP Phone wrong port

[magicstuff]

I have an Atcom AT-610 IP phone and a softphone connected to a 3CX server which is running on an external network over the internet.

Both phones are setup correctly with the 3CX server.

When I dial the softphone from the IP Phone, the softphone rings, and can hear me however I cannot hear audio from the softphone. However, when dialing the IP Phone from the softphone, it does not ring at all.

In the server logs, I noticed that the softphone is trying to connect to the local IP of the IP Phone (192.168.0.10) from the 3CX server, which is obviously never going to work as the 3CX server is on another network and I'm accessing it over the interent.

I have 3 softphones configured that all work fine, it is just this hardware IP Phone that has the problem.

I suspect that this is something to do with the phone configuration, can anyone reccomend something for me to try?

 

[eagle2]

This is a NAT/firewall problem.
May be the STUN server is not configured correctly, etc.

Are your softphones using 3CX tunel ?
Can you see what are the addresses with which the hardphone and the softphones register in 3CX?

Regards

 

[magicstuff]

When the softphones register in 3CX they are using the external IP - 88.xxx.xxx.xxx:1025

When the hardware Phone registers in 3CX it is using the internal IP - 192.168.0.10:5060

The softphones are not using the 3CX tunnel, and I have forwarded the required ports on the router to the IP of the hardware phone.

 

[leejor]

When the hardware Phone registers in 3CX it is using the internal IP - 192.168.0.10:5060

As eagle2 pointed out, it is most likely caused by STUN not being enabled on the device.

Also...when using more than one SIP device behind the same remote router (the SIP server is located on another network), be sure to give each device it's own , unique port number, 5060, 5061, 5062...etc.

You may still experience one way audio if you have too many devices behind the same (remote) router, some routers become confused when handling the voice ports to multiple devices.

If you continue to have a problems, you may want to consider running the 3CX proxy server at your remote location.

 

[magicstuff]

I have enabled STUN on the hardware phone using stun.3cx.com, and given it the local port of 5061, however it still registers with the internal IP on the server.

How can I go about installing the proxy server on my remote server?

 

[SY]

http://www.3cx.com/forums/no-incoming-calls-19487.html#p103250
nothing special, but it is related to the problem.

 

[magicstuff]

@SY: Thanks for the suggestion, however that is already enabled in the 3CX server.

 

[SY]

@SY: Thanks for the suggestion, however that is already enabled in the 3CX server.

Please provide additional information about devices which are implementing selected route between phone and 3CX PhoneSystem:

Atcom AT-610 IP phone<->LAN1<->LAN1router[LAN1firewall]<->internet<->LAN2router[LAN2firewall]<->LAN2<->3CXPhoneSystem_HOST

http://www.3cx.com/forums/forum-rules-read-to-get-answers-93.html

 

[magicstuff]

The 3CX Server is hosted in a datacenter in the UK, so I do not know what network configuration they have. Therefore, I also do not have access to the remote firewall, or the ability to put another machine on the remote LAN unless I rent another server in the datacenter.

AT-610 IP Phone <-> LAN1 Router & Firewall <-> Internet <-> Remote Datacenter LAN <-> 3CX Phone System Host Server

I'm guessing that I need to use a proxy server or 3CX Tunnel to get around this?

 

[leejor]

If all else fails.....http://www.3cx.com/blog/releases/sip-proxy-manager/

 

[eagle2]

The problem should be the router at remote office or the hardware phone.

Magicstuff says the softphones are working fine without 3CX tunnel, this means they are set to register to public address of 3CX server (somewhere) and this is working. The setting 'out of the office' means STUN server is involved.

The problem is with this specific hardware phone and its settings - it is in the same LAN environment, unless something else is configured. No reason for not getting the same result - it is either STUN or SIP ALG is not functioning properly, the difference could be the default port of the phone is probably 5060 (and is monitored by SIP ALG), while the 3CX softphones use random ports.
If the suggestion about SIP ALG is true, disabling STUN in the phone or disabling SIP ALG in the router should fix the problem (you should see registration with the public address of your remote router in your 3CX server). Try also changing the default port of this phone (I think it is not on the list of supported devices). Can you try using another brand / model of IP phone, presumably supported one?

Regards

 

[magicstuff]

I have setup the hardware phone to use a different port - 5061, however it still does not work.

I do not believe that my router (Netgear DG834) supports SIP ALG, so will I need to use the proxy server?

Correct, my phone is not on list of supported devices, and I do not have access to another phone to test this.

 

[eagle2]

Try other port 5062, 5065, 5070, etc.
The reason is port 5061 is also monitored by SIP ALG in some routers (used for secured SIP).

Try disabling the STUN also, infact combinations port 5060 + STUN, port 5062 + STUN, port 5060 w/o STUN, port 5062 w/o STUN. You need to see at 3CX server registration of the phone with public addressort. This still is not a guarantee, but a prerequisite.

If the phone is not the supported list, this doesn't means necessary it will not work, they are many such phones which work fine.

The other option is to set 3CX proxy server at your remote location or consider testing with other router. I have a Netgear WGR614v9 and it IS supporting SIP ALG, so I had to switch off STUN in order extensions to work fine. I didn't found a way to switch off SIP ALG. Normally STUN and SIP ALG are not working together.

Regards

 

[magicstuff]

@eagle2, I tried each of the things you suggested, and using port 5062 without STUN worked perfectly.

Thank you so much, you've solved a problem I've had for nearly a week now.

 

[SY]

@eagle2, I tried each of the things you suggested, and using port 5062 without STUN worked perfectly.

Thank you so much, you've solved a problem I've had for nearly a week now.

Does it mean that the problem was resided in the selected part of the scheme?

Atcom AT-610 IP phone<->LAN1<->LAN1router[LAN1firewall]<->internet<->LAN2router[LAN2firewall]<->LAN2<->3CXPhoneSystem_HOST

 

[magicstuff]

@SY, yes it must have been the router on the LAN with the IP Phone.

 

[SY]

Thanks for answer...
this "bug" is common for many gateways which are trying to declare itself as "SIP comlaint" (SIP ALG is built in)
Interesting, where from they take this c..p of software?..

 

[magicstuff]

Hmm, okay interesting.

I don't recall seeing that my router had SIP ALG built in, but there isn't an option to configure it on the web control panel.

Haha yeah, good question!

 

[eagle2]

Several inexpensive Netgear routers I've tested have built-in SIP ALG and it is working correctly - you don't need to set STUN, etc.

The NAT in Netgear is recognized as symmetric NAT and you can have many SIP clients behind NAT - there are no collisions, etc. You may talk between SIP extensions (typical issue with other routers, RTP being lost, or one-way audio). SIP clients usually show up with public_address:1024, next with port 1025, etc. I didn't found a way to disable SIP ALG in these routers, they are not mentioning even a word about in documentation (also sometimes referred as SIP NAT). The 'ALLOWSOURCEASOUTBOUND' parameter in 3CX server is irrelevant in this case (SIP clients work with it set to ON and OFF), so this means for me, the SIP ALG is applied. I noticed also that enabling STUN is creating problems for SIP devices using port 5060 and 5061 (generally STUN is not working with symmetric NAT).

Utility which could check the NAT at remote site (like firewall checker in 3CX server) will be very precious. Some kind of such diagnostics utility is found in Bria, X-lite softphones. Other option is running Wireshark. It may save lot's of time. NAT/firewall problems are significant majority of issues, posted into the forums. There are less topics concerning 3CX as a phone system,

Regards