Updated README

[TheCodeHermit]

I added steps at the Configuring Truenas Routing ' ' ' after step 14 detailing how to allow incoming traffic from the tailnet to be routed on the local network. Obviously changes can be made but these are the steps I had to take to get my setup 100% working and wanted to contribute as this guide got me most of the way there.

[KornelJahn]

Thank you for your comment and PR, but as I have written in the introductory part,

This guide is based upon the great How-To by AndrewShumate on installing Tailscale in a TrueNAS Core jail. At the end, he recommends to turn the Tailscale client in the jail into a subnet router via the --advertise-routes command-line option. This guide, however, takes a different approach by not activating the subnet router functionality Tailscale itself, but turns the jail itself into a router using IPFW.

If you would like to turn the jail into a subnet router using --advertise-routes, then you do not need to set up IPFW NAT at all, because the Tailscale daemon will handle routing for you. I, however, do not wish to activate this functionality in my case, this is basically the reason why this guide was written.

Right now, I am quite busy and I have not had the time to deal with the newest issues (like #3), but I will repeat the whole installation process with the newest versions to check whether the whole procedure still works. IPFW has been a brittle component as you can see from my past experiences described at the end of the readme.