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)_/¯)