ATA connection to v20 SMB Free

[Bswenson]

Is it possible to connect an ATA device (Grandstream) to the SMB Free 10 version that is hosted by 3cx? I have setup "generic ip phone"so i have Auth ID and password but I cant get an ATA to register. I get the idea behind a SBC is to keep all the traffic coming from a single point in a network...but how about an ATA here and an ATA there...Such as at 2 different homes offices, coming from 2 different IP addresses. Seems pointless to need a SBC just to connect a single device; especially when the apps are basically direct sip connecting anyway. I dont see any logs in the SMB Free 10 version to give me any feedback about attempted registrations or blocks like I can see in my self hosted v18 enterprise. Anyone?

 

[Bswenson]

Ok so update here. I figured out that i needed to uncheck "block remote non-tunnel connections" under options for the user. Now the registration is complete and works. What i do notice though is that when setting up a "FXS" under the DECT/FXS in the voice & chat menu, I can configure the Device (GXW4008) using HT818 or GXW4216 models. The config XML file downloads and I upload it to the GXW4008, the registrations connect; EXCELLENT. 3cx shows the user "green" however the device never shows as connected; and it seems making changes to the device to manage the users on the FXS ports within 3CX never is pushed or pulled from the GXW4008. Any thoughts on what isnt communicating to keep that connection?

 

[Guillaume Bourgeois]

Install an SBC on your network and configure your FXS to register with the SBC.
The issue is NAT traversal; you need an SBC to help it bypass the NAT.

https://www.3cx.com/blog/docs/sbc-r... Border Controller,either privately or by 3CX.

 

[Bswenson]

Install an SBC on your network and configure your FXS to register with the SBC.
The issue is NAT traversal; you need an SBC to help it bypass the NAT.

https://www.3cx.com/blog/docs/sbc-router-phone/#:~:text=The 3CX Session Border Controller,either privately or by 3CX.

Guillaume,
Im not sure if you read my update. The FXS device is connected. I think the SBC is POINTLESS for a single device or maybe even 2 on a distant network. THE FXS device deals with NAT already and has its own section to add it in 3CX; yes it can be shown to add via a SBC but that is an extra piece of gear. So summary recap, extensions are registered and working; the FXS device however isnt calling into 3cx to report and request updates.

 

[Guillaume Bourgeois]

A 3CX SBC is not just a gateway... it's a multi-service device; it handles NAT traversal on its own via an encrypted tunnel. It also acts as a PnP relay. So, it's nothing like what an FXS or a phone (without router functionality) could manage.

I'm not sure you fully understand the complexity of managing NAT.
Your device (FXS) needs to identify its public IP and the port it's using before sending SIP packets.
The goal is to specify the correct source IP address and port in the SIP packets so the server replies to the right source.

You mentioned that your device manages NAT – great, but how exactly? RPORT? STUN? TURN? ICE? SIP ALG (router) ?
Have you confirmed that it's working correctly?

Even if you manage to register, it doesn't guarantee that calls will work, and if calls do work, it doesn't guarantee that the audio will function properly. And even if the audio works, it doesn't mean your device will remain stable and operational.

There are many factors to consider.

3CX provides the solution: install an SBC. You can even install it on a Windows computer, as long as it stays on and is always connected to the internet.

If you're unable or unwilling to install a 3CX SBC and rely on the FXS device to manage NAT traversal on its own, you should contact the FXS manufacturer for assistance with its NAT traversal features.


@JohnS_3CX shared an analogy that I love here :
So, when you say that NAT traversal works in some cases and not in others, it's like asking me why rolling the dice sometimes gives you a six and other times a one.

( John didn’t explicitly grant me reproduction rights, but I imagine he won’t mind, lol. )