SBC - 3CX Tunnel si UP but phones cannot subscribe

[ICTSolutions]

Hello,
we have two remote locations. First is already connected via SBC. Now we deployed SBC for the second location. Difference is that SBC has two NICs. One is connected to provider network with static route to PBX and second NIC is connected to local VoIP network with default route.

3CX Tunnel is UP on new SBC but no communication from phones to pbx is passing via tunnel. We checked it in debug mode. Via tcpdump on SBC we can see multicast packets from phones, but there are not entering tunnel.

In firewalls traffic between SBC and PBX is allowed.


Notes:
3CX PBX is based on Linux
SBC is based on Linux Debian
All 3CX versions are latest.


Thank you for the help

 

[eddv123]

I haven't ever tried or heard of anyone using the 3CX SBC on a device with 2 NIC cards.

This is not a supported setup I would expect, 2 NICs on PBX only.
https://www.3cx.com/blog/docs/network-configurations-supported-3cx-phone-system/

Why have you a connection to the provider off of the SBC, it should really be for phones only - provider connection should be on the PBX only.

 

[leejor]

I agree with eddv123 and before before I got down to his post, I was thkinkg the same thing as what he put in the first line of his reply., the SBC should be a stand alone device, not simply an add-on to another system, and especially not with a second NIC

 

[cobaltit]

Which of the letters in SBC stand for forward?

As others have said this is not a supported setup.Not sure why you would try to do something different when you already have a site that is working.