Adding multiple WAN interfaces makes the most sense when we have more than one internet connection. If you are completing this recipe in order to understand the process of configuring multiple WANs, and you have both a broadband and mobile internet connection, you can use these as your two connections. Otherwise, you will want to acquire two internet connections, preferably from two separate ISPs (otherwise, if you acquire two connections from the same ISP, then both connections to the internet will likely go down if your ISP experiences problems—hardly the redundancy and high availability we seek). If you have no choice but to use a single ISP, it might be helpful to obtain connections with different types of cabling; for example, a broadband and a DSL connection, to minimize the chances that both will go down at the same time.

Configuring a multi-WAN setup involves several steps:

1. Adding WAN interfaces to the firewall and configuring them
2. Configuring DNS servers for each of the WAN interfaces
3. Forming gateway groups and adding the new WAN interfaces to them
4. Adding firewall rules for each new gateway group

We will assume that the additional WAN interfaces have already been physically added to the firewall. We will also assume that our ISP assigns IP addresses via DHCP.