multiple remote extension problem

[zman574]

I have completely racked my brain on this..... I have reconfigured 20 phones and 5 routers 6 or more times each from scratch and this thing keeps failing.

Here is the issue..... I get one phone hooked up and it works great no issues anywhere.

Now I connect a second phone......(fyi this is a remote site home office works fine)

the second phone can sometimes call other extensions but never the first extension that I hooked up at the remote site, but the first phone can call the second extension and everything works except for the audio on the second phone, that will not send any sound from the second phone, so i get two way audio proper function on the first phone and the second phone only has incoming audio no outgoing.

The second phone also can not call out. When the second phone is called from another exetnsion outside of the remote site or from a cell phone there is no audio. The second phone is also unable to make any calls.

This is happening at multiple sites with multiple isp's all remote sites using a router with full cone nat enabled

ports 10000-20000 at the home site are all forwarded to the pbx server.

I really do not know what to do anymore with this...... Do I need full cone nat router enabled at the home office.

It seams to me like the signals are getting messed up someware and using the same ports or signals get sent to the wrong phone.

If i shut down phone 1 the working phone and then reboot the router at the remote site phone 2 will then work fine but when I plug back in phone 1 now that one will not work.

Please help, phone ports are being provisioned in a few days and I have lots of installing left to do on several remote sites for this project.

Thanks

Jim

 

[zman574]

Well after several hours of messing with this problem I finally found the answer to my own problem. The problem is with remote phones you can not share port 5060 with all remote phones. What I had to do was set the ip address of each phone to static at the remote site..... then I had to do port forwarding for each phone to a differnet sip port, I then opened up all my sip ports 5060-5090 on the pbx side. It worked beutifully.

so for example here is what I did.

phone 1: ip 192.168.1.3 sip port 5060; port forward port 5060 to 192.168.1.3 on the remote router

Phone 2: ip 192.168.1.4 sip port 5061; port forward port 5061 to 192.168.1.4 on the remote router

on the pbx side port forward 5060-5089 to 192.168.1.150 (ip address of the pbx system)

I hope this helps anyone else who has found this issue to get through it much more quickly.

 

[leejor]

Yes, every device at a remote location behind NAT has to have a unique port number. I explain this to non-network people like this, think of the public IP as the address of an apartment building and the port numbers as apartment numbers.

 

[zhangjx99]

Hi, I thought for multiple extensions in remote site, we should deploy a 3CX Tunnel proxy server (XP or server), which will help to reduce the bandwidth needed significantly.

Question: Will this port problem happen to proxy deployment too?
Thanks. JX

 

[zman574]

I am running cisco 504g phones it was highly recomended to me to not use the tunnel, plus my client does not want to have to dedicate a computer at each of his businesses for the phones as it will add one more place that could cause phone issues. I am not sure if the tunnel will help to reduce bandwidth needs or not, that is the first I have heard of that, I would be interested in a confirmation of that, if someone has done some testing on bandwidth usage.

 

[zman574]

On these remote extensions everything is working fine except one remote location can not dial another remote location by dialing extension direct: Let me give an example

Extension 8101 at pbx site
extension 8201 at remote site A
extension 8301 at remote site B

8201 and 8301 can both dial and connect to 8101 without an issue.

if 8201 calls 8301 directly no audio on either end and the same if 8301 calls 8201

However if 8201 calls into a voip provider line say 207-555-5555 then dials 8203 from digital receptonist everything works fine.

I have come up with a work around for this but it is not as good as being able to dial the extension direct.

My assumption is that there is another bit of traffic passing over the same ports on both 8201 and 8301 when one tries to connect to the other. Does anyone have a way to solve this issue?

Thanks

Jim

 

[carolinainnovative]

Looks like you are running into a firewall/nat issue with the RTP ports. It works through a voip provider because the voip provider probably has "PBX Delivers Audio" turned on - and thus the calls are literally routing through your home office. Extension to Extension, the RTP packets are sent directly between the two phones (and across the two firewalls - but NOT to the home office) - and so are likely running afoul of nat/firewall rules.

Make sense?

One way to test this theory is to turn on PBX Delivers Audio on both phones and try to call each other. "PBX Delivers Audio" increases overhead to your 3cx system and makes all the extension's traffic route through the pbx, so solving the nat/fw issue is a good PERMANENT option - but to test temporarily, try that setting.

 

[zman574]

I will test on Tuesday and repost most results when I finish testing. Thank you for the information that makes sense and seams like it will work.

Thanks

jim

 

[m4f1050]

Well, here is my problem with "multiple remote extensios" which all falls in same category....

I am running 3CX Phone for Android, and when using 3G if my IP addy changes I have to re-register phone, when I check the PBX server I notice 2 phones listed on same extension, when I try to call the extension I don't get the call, why? Yep, it's trying to route to the disconnected one. Is there a way to end registrations when same extension registers? This would solve my issue. Thanks!