IPTABLES SCRIPTS NOT WORKING
I have tried to implement iptables rules using two different bash scripts and both times after I cannot update or upgrade…it just freezes using apt-get update && apt-get upgrade and tried using apt -y update.
The rules are as follows:
!/bin/bash
iptables -F
iptables -X
ip6tables -P INPUT DROP
ip6tables -P FORWARD DROP
ip6tables -P OUTPUT DROP
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
iptables -A INPUT -m conntrack –ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -m conntrack –ctstate ESTABLISHED -j ACCEPT
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -i eth0 -j ACCEPT
iptables -A OUTPUT -i eth0 -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
iptables -A INPUT -m conntrack –ctstate INVALID -j DROP
iptables -A INPUT -p tcp –dport 22 -m conntrack –ctstate NEW,ESTABLISHED -j ACCEPT
I have also tried these rules:
!/bin/bash
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -m state –state RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp –dport 22 -m conntrack –ctstate NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
iptables -A OUTPUT -m state –state ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -o eth0 -p udp -m udp –dport 53 -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp -m tcp –dport 80 -m state –state NEW -j ACCEPT
ip6tables -P INPUT DROP
ip6tables -P FORWARD DROP
ip6tables -P OUTPUT DROP
Any suggestions welcome please. Just trying to secure it as much as possible