How to Install Tailscale on OPNsense

Instructions

1. Log in to OPNsense and activate SSH and root login and password login.

   echo 'PermitRootLogin yes' >> /etc/ssh/sshd_config
   service sshd restart
   
   # Set root password
   passwd

2. Increase the disk size of OPNsense to at least 12 GB to avoid DiskPressure and Evicted Pods issues.

   df -h
   
   # If the usage is high, add more space to the disk
   # For example, to add 10 GB of space:
   gpart add -s 10G -t freebsd-ufs da0
   growfs /dev/da0p2

3. Update OPNsense to the latest version by going into the default menu via console or SSH and selecting 12. You might need to do this a few times to get to the final version.

   opnsense-update -T opnsense-devel

When asked for updating to a major version, do not select 'y' as this will only cause a minor update. Type in the version number instead (it will be shown in the shell).

4. Additionally, enable Swap.

   mdconfig -a -t swap -s 4g
   swapon /dev/md0

5. Follow the tutorial: WireGuard mesh network using OPNsense. You can use the following command to set it up in one step (adjust IP range to your exposed IP range):

   cd /usr/ports/security/tailscale
   make install clean
   service tailscaled enable
   service tailscaled start
   tailscale up --advertise-routes=172.16.103.1/24

Note: If you still encounter problems regarding missing swap, you can shut down the k3OS VM and temporarily increase the CPU and memory of OPNsense.