How to setup iptables for webserver on ubuntu 14.04?

Question

iptables

Good afternoon colleagues, there is a server on ubuntu 14.04, you need to configure iptables for the web server is apache2 + nginx.
I just started to study Iptables and therefore I don’t really understand it, I will be glad for any help!

Answer 1

Allow connection via ssh and http\https to the INPUT chain. In the same place, allow a local loop.
Set the default policies for the INPUT and FORWARD chain to DROP.
It should turn out something like this:

#!/bin/bash
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT

iptables -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -i lo -j ACCEPT

iptables -A INPUT -p tcp -m conntrack --ctstate NEW --dport 22 -j ACCEPT
iptables -A INPUT -p tcp -m conntrack --ctstate NEW --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -m conntrack --ctstate NEW --dport 443 -j ACCEPT

The last three rules can of course be combined into one via -m multiport.
The rest can be added as needed.
Well, it would be nice to close ssh either to the ip-address of the office, or to configure some kind of fail2ban.