How to leave open port only for localhost?

Question

Nginx

On the nginx server, a NodeJS application is proxied from port 3000. I want to leave only the 22nd and 80th ports on the server for access from outside, and close the rest so that nginx continues to proxy 3000th.

Answer 1

iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -j DROP