Enable TCP/UDP passthrough to tailnet via Public IP

display-chains.bash

sudo iptables -L -v -n

reset.bash

# Clears all user defained chains

sudo iptables -F
sudo iptables -X
sudo iptables -Z

script.bash

# Enable IP forwarding
sysctl -w net.ipv4.ip_forward=1

PORT=<SET>
TAILSCALE_MACHINE_IP=<SET> # Can be a subnet IP if you're using a subnet router!

# Repeat for each port you want to forward
# Set eth0 to your relevant networking interface (on the proxy)
# 
sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport $PORT -j DNAT --to-destination $TAILSCALE_MACHINE_IP:$PORT
sudo iptables -t nat -A PREROUTING -i eth0 -p udp --dport $PORT -j DNAT --to-destination $TAILSCALE_MACHINE_IP:$PORT
sudo iptables -t nat -A POSTROUTING -o tailscale0 -j MASQUERADE

# Above rules are not persistent, so install a package to help us make it persistent
apt install iptables-persistent

# Make all changes to iptables persistant!
sudo netfilter-persistent save