Forward traffic.

echo "net.ipv4.ip_forward = 1
net.ipv6.conf.all.forwarding = 1" | sudo tee /etc/sysctl.d/routing.conf > /dev/null
sudo sysctl --system

Masquerade.

• For nftables, add table below to /etc/nftables.conf and then run sudo systemctl enable nftables && sudo systemctl start nftables.

  table inet nat {
  	chain postrouting_srcnat {
  		type nat hook postrouting priority srcnat; policy accept;
  		oifname "eth0" counter masquerade
  	}
  }
  

• For iptables.

  sudo iptables -t nat -I POSTROUTING -o eth0 -j MASQUERADE
  sudo iptables-save | sudo tee /etc/iptables/rules.v4 > /dev/null