Iptables

Is a simplewall Software on Linux

Setup

• -p: protocol
• --dport or --dports: ports
  • -p is required

Example

sudo iptables -A OUTPUT -o eth+ -p udp -m multiport --dports 53,1300:1302,1194:1197 -d 141.98.255.0/24,193.138.218.0/24 -j ACCEPT

Persistence

• Install iptables-persistent
• Update rules with
  • sudo iptables-save > /etc/iptables/rules.v4
  • sudo ip6tables-save > /etc/iptables/rules.v6

Reset

sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT
sudo iptables -t nat -F
sudo iptables -t mangle -F
sudo iptables -F
sudo iptables -X

Troubleshooting

unknown option --dport

• Check that the protocol is defined, like -p tcp
• Check that you run as root