ISP Failover with Bandwidth

I was wondering if someone can help figure out a solution for isp failover with Bandwidth?

Let me explain our setup:
We have two isps coming to our office (Verizon Fios and Comcast) with a block of 5 static ips for each. Verizon is our primary isp and comcast is our secondary isp. Freepbx has 2 nics installed in the machine. One nic goes directly to our primary isp. The second nic goes to a switch with all our phones connected to it.

The questions I have is:
1)Do I need to install a third nic in the freepbx box for the secondary isp?
2)Since you have to give Bandwidth an ip for your PBX, how do I have it automatically failover from Bandwidth? We use “DNS made easy” for our mail server failover and it works great. Can I use something similiar for voip?
3)If I have to install a third nic, do I need to make any routing changes for Freepbx to work correctly?


you are going to have to do a couple things.

First you will need to get a router that can handle two WANs and address the failover for you. Asterisk is not going to be able to handle it (at least not for the outbound).

Then for your service with, you will need to create an SRV record for your two static IPs on the two carriers. You will create it such that your primary services is used and only in the event that it can’t be reached will the secondary service bet tried. supports SRV records and this is the best way to handle that situation, and it works great.

I finally figured out the piece with I will just make the endpoint in and it can do failover for the ip. That works great because it notifies me when my primary isp goes down.

The part I am confused about is CentOS. In the past we tried to get Freepbx to work through Sonicwall Firewall router and it was a nightmare because nat’ing and voip in Sonicwall do not play nice. We would get dropped calls and/or one way audio so from that point on, I have always connected it directly to the isp and managed the firewall rules on the Freepbx box.

What have you done or used on the Freepbx box to make failover work for the nics?

Did you put two nics in the box and get it working that way? or did you put in a device between the Freepbx and isp (Also, which device did you use)?


getting two WANs to work connected to your FreePBX box will be a nightmare, trust me.

It can be done but is excruciatingly complicated. If you want that scenario to work, get a router designed to do WAN failover.

You happened to have picked one of the most problematic routers (sonicwall) that made you run into your past experience. There are plenty of firewall/routers that work find and don’t gibe you the type of problems that you may have run into with the Sonicwall.

I got it working with 3 network cards and “WFS - WAN Failover Script - switches to a backup WAN connection when the primary link fails” located: