Solved Fanvil X6U (v1) Plug n Play does not register via SBC

[slightlyevolved]

We have hosted 3cx, with a Linux SBC on our network. We have some Fanvl X6U phones that never propagate into 3cx via our SBC.

The phones figure out LLDP-MED fine and switch to our voice VLAN that also is the subnet with our SBC. They then pull a valid DHCP lease, but that's all. I get an update prompt on the phone display for User/Pass but it never shows up in the dashboard phones listing for me to add it.

If I go into the phone web admin and enable the Vendor Identifier, it will pull DHCP option66 from my DHCP server. I can manually add the phone and mac address in 3cx and it'll work. But why is the recommended method of using PnP not working?

Have I glazed over some step in the instructions I'm missing?

Edit: Oh, phone firmware is 2.4.12, the current supported version and updated from the 3cx firmware site.

 

[JohnS_3CX]

Hi,

When you reset the phone, does it appear as a new phone in the Phones page in bold?

 

[slightlyevolved]

That's a negative. It never shows up. I've even pulled another one out of the box (OOB firmware is 2.4.2, these are all Fanvil X6U v1 phones):

- Plugged in. PoE negotiates correctly and LLDP-MED puts it on the voice VLAN and assigns a valid IP for that subnet. Same subnet as SBC controller (SBC installed using 3cx Linux iso inside a Proxmox VM.)
- Phone does not do anything else aside from asking for language selection.
- Access web admin page for phone, no configuration, still has default login.
- Reboot phone.
- Phone returns so the same language selection (unless I've chosen English)
- Upgrade firmware from 3cx firmware page to v2.4.12
- No change. Phone still has no configuration and never appears in the 3cx dashboard.

 

[JohnS_3CX]

Hmm oh boy that's quite a bit of complexity, you might have to simplify things a bit..

Ok in this case you are facing issues most likely due to your VLAN setup preventing SIP multicast PnP messages (at 224.0.1.75) from ever reaching the 3CX SBC. If these messages do not reach the SBC, then 3CX cannot see the phones as new in order to allow you to assign them to their extensions.

Also we do not support nor test Proxmox deployment - not sure but this might also be blocking your PnP multicast due to its network interface. Either use a supported hypervisor or spend the time to troubleshoot multicast traffic. Either way the virtual NIC must be joined in the same network as the phones with no NAT int between them, and multicast messages must be allowed to travel across the network.

So some troubleshooting suggestions:

a) get rid of the VLAN, and test your phones on a simple network without any fancy LLDP / DHCP setups to make sure they work first. If you must have a VLAN, at least make sure the tagging happens on the switch ports so the phones will be entirely agnostic to the existence of the VLAN, and allow multicast on it in case it is currently blocked.

b) use a test pc or laptop plugged into the same switch to run your SBC. If this works then try to introduce your VM SBC again. You might have to switch to a different hypervisor in case the one you use now has virtual interfaces that prevent it from seeing the phones and multicast directly.

I hope this information is somewhat useful, and happy hunting!

PS: Also check the 3CX IP blacklist, ensure none of the phone IPs are blocked - just in case.

 

[slightlyevolved]

I had figured it was a multicast issue, so I also had some feelers out to our network vendor support to check our config as well as this.


There was a misconfiguration on our router for IGMP. Fixed that and the phone showed up in seconds. I can't blame this one on DNS.

 

[JohnS_3CX]

Glad to hear, lucky break! Yeah this is one of those rare cases where you can't blame DNS