Two NICs, Dedicated Internet and Polycoms

Hi All!

I have a question regarding using two network cards with the FreePBX distro as well as a dedicated internet line for a client.

The client currently has 2 ISP coming into the building: one for data and one for voice. However, he is using the PC port of the Polycom VX400 phones to plug in the computers and have internet access.

Together, we installed and configured the FreePBX distro to his specifications, but he was asking my advice on how to go about using the separate internet line strictly for voice.

How would we go about doing this? From the way I understand it, he can connect the server to the switch that all the phone will be plugging into; this will put them on the same network. HOWEVER, since when you utilize the PC port on the Polycom VX400 phones, that will automatically use the network that is connected to the switch, which would be the internet dedicated for data, therefore making the second line not in use.

Is there something that I’m supposed to do in FreePBX to ensure that all local and outbound calls are routed through the secondary NIC card which will be connected to the dedicated internet line for voice? Is it something that I should be doing on the phones?

Any and all help would be appreciated. Thank you in advance!

It sounds like you need to specify a dedicated route to the ISP through that specific interface. In the trunk specification, you enter the IP address of the remote SIP provider. You can use the system routing table (or the router’s routing table) to identify the route to that specific address.

The question I have is how are the phones connected? It sounds like you have an external interface with your public address on one NIC and an internal interface with a NATted address connected to the phones and computers on the other. If that’s the case, you aren’t going to be able to just connected the Voice Line to the computer. In fact, I’m pretty certain you have a router in front of the PBX, in which case, you should consider modifying the router to accept both lines and manage the traffic there. The picture should end up looking a little like this:

Line 1+
… -------- Router ------- PBX ------ Switch ------ Phones
Line 2+

Set the router up with a default route to the regular ISP on line 1 and a dedicated route to the VOIP service on line 2. The problem is that you have no control over how the traffic to the router from the outside is routed - it could come in on either line (or both) when going to the PBX.

Having said all of that, without knowing what your actual network topology is, it’s hard to say exactly what you need. I can think of about four ways that this could be set up that would work. A lot depends on your specific setup.

Consider using VLANs for voice and/or data. Then route as appropriate (OS stuff)

We have a couple of clients like this, with 2 ADSL lines due to high ISDN/lease line costs in the UK,
even with ‘cheap’ ADSL router/modems, just set the default gateway for internet on one IP and use a different IP for the ‘voice line’.

For example from one of the clients I set-up:-

internal network of
data line modem/router on IP on
voice line modem/router on IP on

DHCP address range of to netmask default router/gateway of

and they use the to for static IP’s on servers/printers/phones etc.

set the PBX to use the default gateway of

As dicko said, VLANs are the simplest and best solution.

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