SIP Trunk Working in Software, but not in 3CX

[aastitvabeing]

Hi,

I have a SIP trunk with address rj.voip.ims.bsnl.in. The trunk needs to be configured as rj.voip.ims.bsnl.in:80.

So when I am giving the SIP registrar as rj.voip.ims.bsnl.in and Port 80, with an outbound proxy to be same, it is not working in Zoiper.

What may the reason for not working in 3CX?

Regards,
Deepak

 

[aastitvabeing]

The error message, I am getting.
Destination (sip:[email protected]:80) is not reachable, DNS error resolving FQDN, or service is not available.
Where if you note the Zoiper screenshot you will note it is working.

 

[Evolute IT]

Change your PBX nameserver resolvers to Google's DNS. It happens when your provider has a lag in its DNS.

 

[aastitvabeing]

@Frederick Marcoux - Thank you. But how do we do it?

 

[Evolute IT]

@Frederick Marcoux - Thank you. But how do we do it?

Connect via SSH, edit the file /etc/resolv.conf and add these lines on top:

nameserver 8.8.8.8
nameserver 8.8.4.4

Then restart networking or simply reboot.

 

[leejor]

Most of the time, the DNS server "supplied" by your provider, will work with no issues. If you have a Windows computer on the same network as the 3CX server, you can do some network tests. Open a Command Prompt window and Do a Tracert to the URL of your VoIP provider. That should return the public IP and all of the "hops" to reach your provider. You can also try A PING command to the URL or IP. See if there is a difference when using the default DNS server(s), as supplied by your provider, and using the Google DNS servers in the above post. If changing the DNS servers fixes the problem, you may want to have a chat with your ISP as to why there is an issue.

 

[aastitvabeing]

@Frederick Marcoux - Thank you. I added. Now, it has 4 nameservers. Still not working.

@leejor - I am on cloud VPS. I have tried the connection with most windows and android apps. And the SIP ID of the service provider is working in all app.

It is confusing, why 3CX server is not taking it up.

 

[aastitvabeing]

What I am able to understand, 3CX does not communicate to port 80. That is the reason it is failing to connect the SIP server rj.voip.ims.bsnl.in:80

 

[leejor]

It is odd that they do not use the "standard" port 5060 (or something close), like most other providers.

 

[aastitvabeing]

@leejor - Yes, this is odd. After 2 days of research with Android app, I have come to the following conclusions

1. rj.voip.ims.bsnl.in is using port 80. The service is working with most of the apps.
2. The protocol used is UDP
3. 3CX firewall is blocking the port 80. It needs a port above 1000.

This connection is very important for, and I am stuck now, on how to configure. Please help.

 

[aastitvabeing]

@YiannisH_3CX - Hi, I would like you to take this issue, and throw some light on how things can be done.

 

[YiannisH_3CX]

You should not have an issue even if your provider is using port 80. The PBX should query the DNS and try to connect to the IP it is getting from the reply.
Is the provider authentication based or IP based? When i add the provider to my PBX (with fake credentials) i get no reply from that IP address which means that they either are not listening to port 80 or they need to allow your IP in their whitelist.
Since they have SRV records that do point to port 80 however i would think it is a matter of whitelisting your IP.
Try to configure the provider like the image below and do not use a proxy.


This will allow the PBX to query the registrar and decide the port the provider is using automatically.

 

[aastitvabeing]

@YiannisH_3CX - Thank you for your reply.

1. I do understand for the whitelist of IP. But then, how come the connection is working from any app, using other ISP.
2. If the service provider has enabled IP only from India, the 3CX is loaded on Indian VPS, with IP from India.
3. I have configured as you have mentioned. But still the same error.

Destination (sip:[email protected]:5060) is not reachable, DNS error resolving FQDN, or service is not available.

 

[YiannisH_3CX]

Can you send a screenshot of the trunk configuration? Obviously hide the Auth ID of the trunk.
Also do you pass the PBX firewall checker? Have you tried calling them and asking what they are seeing from their side? They should be able to tell you if the requests are reaching them and if they are seeing anything wrong.

 

[aastitvabeing]

@YiannisH_3CX - Please note the screen-shots attached.
This service provider is a Govt. of India enterprise, and the customer helpline is very poor. They are not able to even understand the problem. For them, if it is working in app, it is good.

 

[YiannisH_3CX]

Your settings for registering the trunk look correct and the PBX should try to contact the provider to port 80. You can use wireshark to confirm. Either than that if the provider is no willing to assist you i would recommend changing providers. You could select an international provider from our worldwide list.
https://www.3cx.com/partners/sip-trunks/worldwide/

 

[aastitvabeing]

@YiannisH_3CX - thank you for your update. Why I am trying to go with this particular service provider, is because they are the only company in India giving virtual numbers for IP calling. In India, VOIP telephony was banned. But now it is opened up. It can a huge new opportunity for 3CX for India as a country, if this can be configured. Can you imagine $15.00 per year unlimited calling to the whole of India?

 

[YiannisH_3CX]

In that case you need to use wireshark and see if the PBX is sending the request to the correct IP And correct port. The error you see in the management console is very generic and could be caused by a number of factors.

 

[Rhys Haskell]

You may need to edit the nginx config as it will not allow inbound requests on port 80 by default I believe

 

[YiannisH_3CX]

You may need to edit the nginx config as it will not allow inbound requests on port 80 by default I believe

In this scenario the provider listens to port 80 not the PBX. The PBX will contact the provider from port 5060 to port 80 and will request the provider to contact the PBX to port 5060. The port of the PBX will not change