When we want improved uptime and improved throughput with our internet connection, multiple WAN interfaces providing multiple internet connections provide an effective way of accomplishing this. When you first configure pfSense, you must set up a working LAN and WAN interface. You can have more than one WAN interface, and these interfaces are referred to as OPT WAN interfaces.

To take full advantage of a system that utilizes multiple WANs, you should have separate internet connections. The ideal scenario is one in which you have separate internet connections from separate internet providers. This is because there is a higher likelihood of a connectivity issue between your network and an internet service provider, thus affecting all connections that go to that provider compared to a connectivity issue affecting multiple providers at the same point in time. In addition, if you have two connections to the same ISP and there is a failure of the entire ISP, then both of your connections will go down. Needless to say, this is nowhere close to the redundancy we seek to achieve. Still, if there is only one ISP in your area, two connections will at least provide more bandwidth than one.

In such a case, if you opt for two connections from the same provider, you should try to obtain a second connection that has a different type and path of cabling than the first connection has. Even if you have connections from different providers, this is good practice. Often, connections carried on the same cabling are subject to the same cable cut (and therefore the same outage).

If you have multiple connections, your connections should not only use different cabling, but they should also have different paths to the internet. This might lessen the risk of using the same ISP. This is because in many cases, different types of connections from the same provider use completely different networks and, therefore, take different paths.