Router create script

router.yaml

network:
  ethernets:
    eth0:
      dhcp4: true
      nameservers:
        addresses:
        - 1.1.1.1
    eth1:
      dhcp4: false
      addresses:
      - 172.16.70.1/24
  version: 2

Masquerade

sudo iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
sudo iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
sudo iptables -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
sudo iptables -t nat -A POSTROUTING -s 172.16.70.0/24 -o wg0 -j MASQUERADE
sudo iptables -A FORWARD -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

Enable ip forward

echo 'net.ipv4.ip_forward = 1' | sudo tee -a /etc/sysctl.conf
sysctl -p

IP_Address: 172.16.70.12
Gateway: 172.16.70.1

Enjoy self made router life!

Port forwarding(Sample)

sudo iptables -t nat -A PREROUTING ! -s 192.168.11.0/24 -p tcp -m tcp --dport 30000:32767 -j DNAT --to-destination 172.16.70.12:30000-32767
sudo iptables -t nat -A POSTROUTING -d 192.168.11.0/24 -p tcp -m tcp --dport 30000:32767 -j SNAT --to-source 172.16.42.1:30000-32767

Save iptables setting

iptables-save > /etc/iptables/rules.v4