[CM306002]: There is no valid STUN server specified! External IP can not be resolved.

[kthomeer]

The PBX (v18, update 1 = lastest) is localy hosted on a Raspberry Pi, with dynamic IP.

1/ The PBX works normal, the dynamic IP (IPv4) works normal and correct.


2/ Firewall check is normal:


3/ I tested the STUN servers from command line:
pi@raspberrypi:~ $ stun stun.3cx.com
STUN client version 0.97
Primary: Independent Mapping, Port Dependent Filter, preserves ports, no hairpin
Return value is 0x000017
pi@raspberrypi:~ $ stun stun.voipbuster.com
STUN client version 0.97
Primary: Independent Mapping, Port Dependent Filter, preserves ports, no hairpin
Return value is 0x000017
pi@raspberrypi:~ $ stun stun.sipgate.net
STUN client version 0.97
Primary: Independent Mapping, Port Dependent Filter, preserves ports, no hairpin
Return value is 0x000017

4/ But the log continues to give the same error:
14/11/2021 23:08:29 - [EC100009]: External application [raspberrypi:0/PbxConfigTool] is disconnected:
14/11/2021 23:06:52 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 22:33:32 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 22:00:11 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 21:26:51 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 20:53:31 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 20:20:11 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 20:00:14 - [CM506004]: STUN request to STUN server 77.72.169.210:3478 has timed out; used Transport: 0.0.0.0:5060/UDP fk=0 tgt=
14/11/2021 19:46:51 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 19:13:31 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 18:40:11 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 18:06:51 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 17:33:30 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
14/11/2021 17:08:24 - [EC100009]: External application [raspberrypi:0/PbxConfigTool] is disconnected:
14/11/2021 17:00:10 - [CM306002]: There is no valid STUN server specified! External IP can not be resolved.

I think it's a bug, and I think this is not the first time that it's mentioned (Google Search), but it has never been resolved.

 

[ChrisC_3CX]

First off, could you please provide the information mentioned here: https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

Also, just to confirm, everything works as expected and you actually get the new IP whenever it changes but you are seeing these errors seemingly with nothing else being affected?

I see you're not using the 3CX default STUN servers. Could you please switch back to them and let me know if the same errors continue to appear?

 

[kthomeer]

First off, could you please provide the information mentioned here: https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

Mater of fact, I did already:

• 3CX Version => done (v18, update 1 = lastest)
• Server OS => done (Raspberry Pi, but more precisely: Raspbian GNU/Linux 10 (buster))
• Is the 3CX Server Hosted and where? => local hosted on Raspberry Pi
• IP Phone Make/Model/Firmware version => not applicable for this problem, but one Fanvil X4
• Provisioning Method => not mentioned, but obvious because of local Raspberry Pi
• Trunk Provider or VoIP Gateway Make/Model => not applicable for this problem I think, but it's Intertel
• Has the Firewall Checker passed => done (yes)
• Are custom Phone Templates being used => not mentioned, but no

Also, just to confirm, everything works as expected and you actually get the new IP whenever it changes but you are seeing these errors seemingly with nothing else being affected?

Correct. I don't know if my IP would change, if it will be corrected.

I see you're not using the 3CX default STUN servers. Could you please switch back to them and let me know if the same errors continue to appear?

Which one? There was a problem with it: some domain names had the same IP adress. Thats the reason why I did change.

 

[ChrisC_3CX]

Which one? There was a problem with it: some domain names had the same IP adress. Thats the reason why I did change.

I see, well that is true but give it a shot anyway and let me know what happens. Go into "Settings >> Network" and under "Dynamic Public IP (IP changes)" and make sure the stun servers are set like so:

 

[kthomeer]

OK, it works, but now I get this message:
15/11/2021 15:13:36 - There's another STUN server that resolves to the same IP: 54.37.20.144:3478/UNKNOWN_TRANSPORT fk=0 tgt=; ignored
15/11/2021 15:13:36 - There's another STUN server that resolves to the same IP: 54.39.182.217:3478/UNKNOWN_TRANSPORT fk=0 tgt=; ignored

It's the reason why I did change the STUN server. ;-)

Dig command gives the following results:
stun.3cx.com. 300 IN A 54.37.20.144
stun.3cx.com. 300 IN A 51.38.45.26
stun.3cx.com. 300 IN A 54.39.182.217
stun.3cx.com. 300 IN A 54.39.188.150
stun2.3cx.com. 35 IN A 54.39.182.217
stun3.3cx.com. 31 IN A 54.37.20.144

So, stun.3cx.com already contains stun2.3cx.com and stun3.cx.com.

 

[ChrisC_3CX]

It's the reason why I did change the STUN server. ;-)

Well in that case, I have to say you're going to have to simply ignore the message . It's just that the 3CX stun servers are now within the CDN so stun.3cx.com will resolve to multiple IPs at once whereas stun2.3cx.com and stun3.3cx.com will each resolve to a single ip that's already resolved by stun.3cx.com hence the message you're seeing. I'm afraid you cannot leave the fields empty so I'd recommend leaving them as is.

That said, there's nothing to worry about and what you're seeing is expected.

 

[kthomeer]

Found the sollution ...
Made the following as STUN servers:

• stun2.3cx.com
• stun3.3cx.com
• stun4.3cx.com

No errors any more ...

BUT, it stays strange that only 3CX STUN servers are allowed ...

 

[Cjay]

Found the sollution

Good tip! I posted on this nearly 2 years ago and never resolved the issue. Finally Stun4 seems to have fixed it.

 

[ChrisC_3CX]

BUT, it stays strange that only 3CX STUN servers are allowed ...

It's not that they are not allowed, I only requested that you switch back to the 3CX ones as we have not tested any STUN servers other than our own so we cannot guarantee normal functionality with them.

Using those three STUN servers will indeed get rid of the message as they all resolve to one single unique IP each, but, to be completely honest, I'd recommend sticking with using stun.3cx.com as one of the stun servers as that is the one that resolves to more than one STUN server IP and therefore offers some redundancy. This of course would mean that you would keep seeing the "same IP" message.

Good tip! I posted on this nearly 2 years ago and never resolved the issue. Finally Stun4 seems to have fixed it.

I have to say, I wouldn't call this an issue as it does not affect functionality but is rather just an informational message in the logs.