#!/usr/bin/env ruby

IPTABLES = "iptables"
SERVICE = "iptables"

ssh_port = 22 unless ARGV[0] then ssh_port = ARGV[0]

puts "Flushing rules..."
`#{IPTABLES} -F`

puts "Settings loopback rules..."
`#{IPTABLES} -A INPUT -i lo -j ACCEPT`
`#{IPTABLES} -A INPUT -i ! lo -d 127.0.0.0/8 -j REJECT`

puts "Accepting all established inbound connections..."
`#{IPTABLES} -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT`

puts "Allowing all outbound traffic..."
`#{IPTABLES} -A OUTPUT -j ACCEPT`

puts "Allowing HTTP and HTTPS connections..."
`#{IPTABLES} -A INPUT -p tcp --dport 80 -j ACCEPT`
`#{IPTABLES} -A INPUT -p tcp --dport 443 -j ACCEPT`

puts "Allowing SSH on port #{ssh_port}..."
`#{IPTABLES} -A INPUT -p tcp -m state --state NEW --dport #{ssh_port} -j ACCEPT`

puts "Allowing ping..."
`#{IPTABLES} -A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT`

puts "Logging denied connections..."
`#{IPTABLES} -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7`

puts "Rejecting all other inbound connections..."
`#{IPTABLES} -A INPUT -j REJECT`
`#{IPTABLES} -A FORWARD -j REJECT`

puts "Saving..."
`service #{SERVICE} save`