pfSense: Adding a Second LAN

While this is undoubtedly a beginner’s question, it’s one that I spent most of yesterday wrestling with. I also really struggled to find information on it: how to add a second LAN.

There are plenty of ways of achieving what I want on my network – to subdivide it between devices I trust, and ones I don’t [or at least trust less, such as my IP camera]. The new machine I got to run pfSense on has 4 network interfaces, so I decided to run two LANs straight off the adaptors [leaving one spare for a possible future experiment with IoT nonsense].

Adding the interface is well documented, as is the ‘default allow’ you’ll need to set in the firewall rules. What you also need to do is to configure a DHCP server, which is under the Services menu in the WebGUI. You’ll see there is an entry already configured for the first LAN, which you can use to figure out the settings. Obviously, this assumes that you configured the LAN for DHCP during the setup, which almost everyone is going to want to do.

I set an address range of .2 – .254, and then configured both the DNS server and the Gateway on .1. You’ll also have to set the ‘enable DHCP’ checkbox at the top, which is disabled by default.

While it’s obvious in retrospect, I went in completely the wrong direction, thinking it was something to do with routing rules. Routing is all well and good, but I was never going to get very far without an IP address :).