Failover from SBC to STUN

[David_K]

Hello

I have a customer using Yealink T46 phones configured using a local SBC (3CX server is in the Cloud)
The SBC is down for maintenance.
So no phones anymore.
In the meantime I'd like to switch them to STUN
But not working, the phones can't autoprovision

What's strange is that my autoprovisioning URL https://my3cxdomainwashere/provisioning/25731csy30r does result in a 404 page when I type in in a browser
Maybe it's related?

David

 

[eddv123]

Does an nslookup resolve your FQDN ? have you checked your firewall is configured for the correct port forwarding: https://www.3cx.com/docs/manual/configuring-ip-phones/

I would of thought however that maintenance of an SBC machine = updates. This should not take long enough that switching your provisioning mode would be worthwhile doing.

 

[David_K]

In fact the SBC is DOWN because the host machine had an hardware failure and we are restoring from last backup since almot 3-4 hours now... Quite slow and we are only 40% far...

Yes the FQDN resolves well, I'm using it to connect to the 3CX management UI to change the phone from SBC to STUN.
Thought it was a kind of DNS issue, tried with IP instead, same behavior...

 

[eddv123]

If I had a secondary option after SBC (and my hosted provider supported software firewall) I would create an IPSec VPN, multiple STUN phones in my opinion can cause too many issues. How many phones do you have here ?

 

[David_K]

Only 5
OK I found the issue...
On the phone UI, in Account / Register, they had the option "Enable Outbound Proxy Server" to Enabled (with the IP of the SBC which is quite normal I think)
Apparently when you switch to STUN it does not disable the option.

 

[David_K]

Brings me to : is it possible to have a seconday SBC on the same LAN? Just in case...

 

[JohnS_3CX]

Hi @kleidav76

You can have a secondary SBC if you like, but phones will only be able to use one of the two.

In case SBC1 goes down, if you reset the phones they will appear on the phones tab via SBC2. You can provision them straight away from that SBC and have them up and running in very little time.

A Raspberry Pi can be used as a low cost backup. The 3CX SBC is tested on the latest Raspberry Pi and can be used for a remote office with up to 20 phones and a maximum of 10 BLF keys per device.

 

[craigreilly]

Have the backup in waiting with the same IP information provisioned... just simply turn the old one off and the new one on.

 

[pmterp]

Or if you're willing to venture into the land of unsupported custom templates, some phones (Yealink for sure) can have a 2nd proxy entered with automatic fail over.