What was the command that was entered for this iptables rule

Question

So I have some rules on my server for my VPN, but my partner does port forwarding if needed for my customers. I want to know how to do it myself but he doesn't want to tell me. Now I found these rules on my server, could anyone translate it to the command that was entered? Like the command my partner typed in putty to add this rule, so I can learn from it.

If possible explain what everything does aswell please :).

Picture of rules:

Answer 1

If you do

iptables-save > iptables.txt

Will get the iptables commands, you will need to add iptables in front of them to add just the one line

You can use

iptables-restore < iptables.txt

to restore the iptables rules as they are in the in files.
This is useful for backups before changing things.

Answer 2

Read up the iptables man page to see what each switch/flag does.

iptables -t nat -A PREROUTING -p tcp --dport 1338 -j DNAT --to 10.8.1.1:1338
iptables -t nat -A PREROUTING -p tcp --dport 777 -j DNAT --to 10.8.1.1:777
iptables -t nat -A PREROUTING -p tcp --dport 1122 -j DNAT --to 10.8.1.1:1122
iptables -t nat -A PREROUTING -p tcp --dport 1124 -j DNAT --to 10.8.1.1:1124
iptables -t nat -A PREROUTING -p tcp --dport 1604 -j DNAT --to 10.8.1.1:1604
iptables -t nat -A PREROUTING -p tcp --dport 3030 -j DNAT --to 10.8.1.1:3030