*filter
:INPUT DROP
:FORWARD ACCEPT
:OUTPUT ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m tcp --dport 3000 -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
COMMIT
*nat
:PREROUTING ACCEPT
-A PREROUTING -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3000
COMMIT