Multiple Internet Gateways on Debian Appliance

[kaiserh]

I've had a look over the document on the 3CX blog outlining the different network configurations.
https://www.3cx.com/blog/docs/network-configurations-supported-3cx-phone-system/
I'm planning to use the Multiple Internet Gateways for an upcoming installation and would like to make sure I have it right.

Below is a rough sketch of what I want to do. The ISP offers a dedicated SIP service that is delivered via it's own dedicated Ethernet port on the NTU (so we use two Ethernet ports on the NTD, one for general internet, and one for SIP). The SIP interface is assigned a 10.0.0.0/8 IP address.

Rather than use policy based routing through the router, I'm thinking it will be simpler to have the Debian appliance running on a NUC with 2x Ethernet interfaces. One will be a 192.168.0.0/24 IP address for the phones and 3CX administration, the other will be a 10.0.0.0/8 IP address and plug directly into the NTU, bypassing the router altogether.

From what I can see, I need to edit the /etc/network/interfaces file to add a static route for the SIP server to leave via the 10.0.0.0/8 interface.
So, if the ISP's SIP server is, say, 12.12.12.12 and my SIP interface is 10.0.0.123, then I would need something like:

up route add -net 12.12.12.12/32 gw 10.0.0.123 dev eth1

Is this correct?

 

[NicholasP_3CX]

Hi @kaiserh

eth1 should not have a default gateway.
You would define the static route in the 3CX server as a persistent route. This way it would be available when the server reboots as well.

Please find a quick guide at https://huf.org/wp/?p=394 for the configuration on Debian 10

 

[kaiserh]

That's great, thank you for the super-quick response.

 

[NicholasP_3CX]

Please let us know how it goes. I will keep it open till you confirm