Phones Tab: Local vs Public IP Addresses

[TierList123]

I have a live PBX system with around 40-50 handsets. The client has a firewall which has been set up and working for a few years now. SIP ALG is turned off. However, 2 of the handsets out of the 40 are showing a local IP address in the Phone's tab, while every other handset is registering as a public IP (same static public IP). All the phones are configured in the same way, they are all registered using STUN and the local SIP ports and RTP Audio ports of the STUN settings are correct in their increments. All phones exist within the same premises / network and yet 2 are showing local IP instead of public IP.

What would be the reason for this?

Details:
3cx V18.0 Update 4 (Build 965).
32 SC Enterprise License

 

[NikosT_3CX]

@TierList123 having STUN phones on a 3CX Hosted machine ( since you posted it on our Category ) is not the ideal solution as it is not supported.
Best scenario in order to avoid these kind of issues and having an encrypted communication between the endpoints and the PBX is to use 3CX SBC.
It will save your time and also will provide better security and quality for your customer.


Please check the following :

https://www.3cx.com/ordering/pricing/hosted-info/

What we will support:

• Connectivity issues to/from the service (excluding STUN IP-Phones).
  

 

[TierList123]

@TierList123 having STUN phones on a 3CX Hosted machine ( since you posted it on our Category ) is not the ideal solution as it is not supported.
Best scenario in order to avoid these kind of issues and having an encrypted communication between the endpoints and the PBX is to use 3CX SBC.
It will save your time and also will provide better security and quality for your customer.


Please check the following :

https://www.3cx.com/ordering/pricing/hosted-info/

What we will support:

• Connectivity issues to/from the service (excluding STUN IP-Phones).

Thanks, should I rather post this in general? I am looking for a discussion about why it happens to show local IP's on some handsets and public IP's on others. This is hosted by ICTGlobe South Africa.

 

[NikosT_3CX]

@TierList123 I will move it dont worry at all.
You just posted this to us so i wasnt sure 100% that you are hosted with 3CX or not

 

[JohnS_3CX]

Hello,

Please note that STUN is not considered reliable enough for multiple phones at the same site. Do not rely on the fact that they have been "working ok until now", STUN is not reliable enough in the long run and sooner or later you will notice a mix of: wrong IPs, duplicate entries, one way audio, registration issues, BLF issues, crosstalk. Possible reasons: STUN binding failures, ISP or firewall interfering with SIP messages, device misconfig or firmware bug.

You could probably track it down if you spend enough hours in wireshark, or rebooting everything might simply make it go away until months later it reappears.

Consider installing a 3CX SBC at your phones site, it was made to serve installations like your case and solves practically all STUN related problems you might ever encounter: https://www.3cx.com/docs/3cx-tunnel-session-border-controller/