Raspberry Pi Router and Firewall with OpenWrt
Turn a Pi into a powerful router with VLANs, ad blocking and VPN — between your modem and your network.
OpenWrt is the open-source router operating system used by enthusiasts and many commercial routers. On a Pi 5 with a second Ethernet adapter it routes at gigabit speeds.
Video tutorial
Video by Royalsoft, embedded from YouTube. The written steps below are our own and match the parts list.
Mission steps
Download OpenWrt
Get the image for your Pi model from the OpenWrt firmware selector and flash it with Imager (Use custom).
First login
Connect your laptop to the Pi's built-in Ethernet and open 192.168.1.1 (LuCI web interface). Set a root password immediately.
Add the WAN port
Install the USB Ethernet driver package for your adapter and assign it as WAN, connected to your modem.
Connect Wi-Fi
Plug your existing router in 'access point' mode into the LAN side, or use a dedicated access point.
Harden and extend
Keep default-deny inbound rules, add a guest/IoT network, install adblock or WireGuard packages.
Questions
Will this replace my ISP modem?
No — it replaces the router behind the modem. Put your ISP device in bridge mode if possible to avoid double NAT.