Sometimes, we want higher uptime and a higher throughput with our internet connection, and when we do, multiple WAN interfaces providing multiple internet connections is a way of doing this. Before you implement multi-WAN, you must already have a working LAN and WAN interface. Additional WAN interfaces are referred to as OPT WAN interfaces, and pfSense can support several WAN interfaces.

In order to fully take advantage of a multi-WAN setup, however, you should have separate internet connections. Ideally, you should have separate internet connections from separate internet providers, because there is a higher likelihood of a connectivity issue between your network and a provider affecting all connections to that provider than there is that a connectivity issue would affect multiple providers at the same time. And of course, if you have two connections to the same ISP and there is a failure of the entire ISP, then both of your connections are down – a far cry from the redundancy we hoped to achieve, although such a setup will at least provide more bandwidth than a single connection.

There may be cases, however, where there is only one provider in your area. 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 from the first. This is good practice when using different providers as well, because often connections carried on the same cabling are subject to the same cable cut and therefore the same outage.

Your connections should not only use different cabling, but they also should have different paths to the internet. This is one aspect in which having the same provider may not be that much of a handicap. Often, different types of connections from the same provider (for example, broadband cable and DSL) might utilize completely different networks and therefore take completely different paths.