iptables

minimal.sh

iptables -A INPUT -i lo -j ACCEPT                                                       # Loopback
iptables -A INPUT -p icmp -j ACCEPT                                                     # ICMP
iptables -A INPUT -p tcp -m tcp --dport 2222 -m state --state NEW,ESTABLISHED -j ACCEPT # SSH port 2222
iptables -A INPUT -p udp -m state --state ESTABLISHED -j ACCEPT                         # DNS response
iptables -A INPUT -p tcp -m tcp -m state --state ESTABLISHED -j ACCEPT                  # Established TCP conns
iptables -A INPUT -j DROP                                                               # Drop remaining traffic