iptables

$[texteditor]$

Enable port forward

sudo $texteditor$ /etc/sysctl.conf

net.ipv4.ip_forward = 1

sudo sysctl -p

Add port forward

$[localip]$

$[localport]$

$[forwardip]$

$[forwardport]$

sudo iptables -t nat -I PREROUTING -p tcp -i eth0 --dport $localport$ -j DNAT --to-destination $forwardip$:$forwardport$
sudo iptables -t nat -I POSTROUTING -p tcp -o eth0 --dport $forwardport$ -d $forwardip$ -j SNAT --to-source $localip$

Save iptables (interactive)

sudo apt install -y iptables-persistent
sduo dpkg-reconfigure iptables-persistent
cat /etc/iptables/rules.v4
cat /etc/iptables/rules.v6

Show iptables

sudo iptables -t nat -L -v -n --line-numbers

Delete iptables

sudo iptables -t nat -D PREROUTING [N]
sudo iptables -t nat -D POSTROUTING [N]