SBC and remote phone configuration

[next2]

Hi,

Could someone clarify the exact configuration for
1/ SBC on Debian (Raspberry Pi)
The config wizard asks for the IPBX FQDN, but also for an IP address. Is this the WAN IP address on the IPBX, or the WAN address on the SBC, or the LAN address on the SBC ?
2/ Remote phone on 3CX
When selecting SBC as provisioning method, it asks for the IP address of the SBC. Is this the WAN address on the SBC, or the LAN address on the SBC ?

Thank you !

 

[Philip Darnell]

Hi,

Could someone clarify the exact configuration for
1/ SBC on Debian (Raspberry Pi)
The config wizard asks for the IPBX FQDN, but also for an IP address. Is this the WAN IP address on the IPBX, or the WAN address on the SBC, or the LAN address on the SBC ?

If the PBX is behind NAT then enter the local IP Address of the PBX, if it isn't behind NAT then enter the WAN Address of the PBX.

2/ Remote phone on 3CX
When selecting SBC as provisioning method, it asks for the IP address of the SBC. Is this the WAN address on the SBC, or the LAN address on the SBC ?

Thank you !

This is the LAN address of the SBC

 

[eddv123]

Hi next2,

To confirm - the remote configuration wizard does not require anything in regards to its own configuration - it wants all the information from the connecting 3CX system.

Read here: https://www.3cx.com/docs/3cx-tunnel-session-border-controller/

 

[next2]

Thank you ! I had some doubts as the Windows SBC setup asks for the SBC local IP.
Also, why do we need to input the FQDN and the IP ? Does it mean SBC cannot work with a 3CX installed on a public dynamic IP ?

Thank you,
Thomas

 

[eddv123]

Well there is a point here.

Personally I think every 3CX instance should be behind a NAT for security reasons if anything.

It does ask for a public IP if not, however I would not recommend this. Also this rules out using a dynamic Public IP address on your 3CX instance (it must be static) as if it changes I would imagine your SBC connection would drop (unless it would simply use the public FQDN regardless).

 

[YiannisH_3CX]

Thank you ! I had some doubts as the Windows SBC setup asks for the SBC local IP.
Also, why do we need to input the FQDN and the IP ? Does it mean SBC cannot work with a 3CX installed on a public dynamic IP ?

As you may have noticed the windows SBC does not ask for the local IP of the PBX as this is not mandatory. You can use the FQDN in both locations if you like and the SBC will still connect. The SBC can work with a 3CX installed FQDN and with a dynamic IP. In the dynamic IP scenario however you may have some down time every time the IP changes until the DNS propagation takes place. This is why it is always recommended using a static public IP.

 

[next2]

Thank you for the explanation !

 

[cobaltit]

As you may have noticed the windows SBC does not ask for the local IP of the PBX as this is not mandatory. You can use the FQDN in both locations if you like and the SBC will still connect. The SBC can work with a 3CX installed FQDN and with a dynamic IP. In the dynamic IP scenario however you may have some down time every time the IP changes until the DNS propagation takes place. This is why it is always recommended using a static public IP.

@YiannisH_3CX

Would you mind elaborating on this? We recently moved our internal use instance between cloud providers and after waiting a significant amount of time I ended up rebooting the SBC. A phone configured via STUN at the same location reconnected very quickly. Should we not be putting the public IP in the SBC configuration? How often does the SBC check to see if DNS has changed?

 

[YiannisH_3CX]

Once the SBC loses registration with the PBX because the IP changed it will try to re-register for a few seconds and then it will try to resolve the FQDN again. If the DNS has updated it will connect to the new IP address.