Cloudflare iptables

This is a simple script for people who are running servers behind cloudflare.

For most people cloudflare acts as a reverse proxy for traffic to your website so for the majority of users there is no need for any other external IP to hit their server on HTTP + HTTPS.

The script downloads cloudflares IP ranges and sets rules to allow only those ranges to access the server on http + https (80 + 443).

# cf_iptables
# ===========
# Simple iptables script for cloudflare
# Sets iptables rules to only allow cloudflare IP ranges
# This stops direct traffic from visitors / hackers & means every visitor is
# connecting via cloudflare.
# equk 2014 -
# check if root (required for iptables)
if [ $(whoami) != "root" ]; then
    echo "ERROR: Please Run As Root User (required for iptables)"
    exit 1
# cloudflare ipv4
for i in `curl`; do iptables -I INPUT -p tcp -s $i --dport http -j ACCEPT; done
for i in `curl`; do iptables -I INPUT -p tcp -s $i --dport https -j ACCEPT; done
# cloudflare ipv6
for i in `curl`; do ip6tables -I INPUT -p tcp -s $i --dport http -j ACCEPT; done
for i in `curl`; do ip6tables -I INPUT -p tcp -s $i --dport https -j ACCEPT; done
# drop all others ipv4
iptables -A INPUT -p tcp --dport http -j DROP
iptables -A INPUT -p tcp --dport https -j DROP
# drop all others ipv6
ip6tables -A INPUT -p tcp --dport http -j DROP
ip6tables -A INPUT -p tcp --dport https -j DROP

The script is also available on my github.

I also also posted this script last year (Oct 2014) on reddit as a response to a PHP library. I’ve been using it on servers since 2013.

comments powered by Disqus