Install OPNsense

Download the image and write to usb device#

Image download#

• https://opnsense.org/download

Sounds odd (to me), but choose the vga option if your intent is to boot from a usb.

Create an OPNsense bootable usb#

Get the device name of your usb#

Use something like lsblk

Unmount if necessary umount /run/media/[ user ]/[ device_name ]

Write the image to the usb device#

sudo dd if=OPNsense-25.7-vga-amd64.img of=/dev/sdg bs=1M conv=sync status=progress

Installation steps#

Pretty straight forward, just assign the correct interfaces to WAN and LAN at the end.

Troubleshooting#

NAT isn’t working#

Network works on opnsense server and anything using the WAN interface, but LAN clients have no access - NAT isn’t working.

Interfaces => LAN => Static IPv4 configuration => IPv4 gateway rules => Disabled (I had LAN_GW selected because it’s a gateway for LAN clients ¯_(ツ)_/¯)