The radius ruleset is based on the classic Freeciv rules adopting many ideas from the experimental and civ2civ3 rulesets. It features a growing city radius_sq from 4 to 20: size radius (sq.) vision ...
In this tutorial: We use single-hop tunnels. This is a bit like a VPN, but where you would use a random VPN server every time. The intermediate node will know your IP address, but not what you are ...