setup-tables.sh

# delete existing rules
iptables -F

# drop all traffic not explicitly allowed
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT DROP

# allow ping from inside
iptables -A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT

# allow ping from outside
iptables -A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT

# allow DNS connections
iptables -A OUTPUT -p udp -dport 53 -j ACCEPT
iptables -A INPUT -p udp -sport 53 -j ACCEPT

# allow HTTP
iptables -A OUTPUT -p tcp -dport 80 -m state --state ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -sport 80 -m state --state NEW,ESTABLISHED -j ACCEPT

# allow HTTPS
iptables -A OUTPUT -p tcp -dport 443 -m state --state ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -sport 443 -m state --state NEW,ESTABLISHED -j ACCEPT

# allow SSH
iptables -A OUTPUT -p tcp -dport 22 -m state --state ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -sport 22 -m state --state NEW,ESTABLISHED -j ACCEPT