July 02, 2022
Basic survival guide and commands for iptables
iptables is a Linux firewall tool that manages packet routing and can block or allow traffic based on rules like a packet’s origin or destination.
Its settings are organized in tables which contain sets of rules, called chains, that will filter data packets.
# Check current configuration iptables -L -v # Accept all requests from an IP iptables -A INPUT -s <ip> -j ACCEPT # Drop all requests from an IP iptables -A INPUT -s <ip> -j DROP # Drop all requests from a range of IPs iptables -A INPUT -m iprange --src-range <ip_range_start>-<ip_range_end> -j DROP # Drop all traffic (must be run after acceptance rules) iptables -A INPUT -j DROP # Delete all current rules iptables -F # Persist changes to disk /sbin/iptables-save # Depending on your setup, you may need to run another command instead netfilter-persistent save