DDNS manager script using CloudFlare. DDNS for free! :)

cf-ddns.sh

#!/bin/sh
# --------------------------------------
# CloudFlare DDNS Manager
# --------------------------------------
# This script checks if the WAN (public) IP address is different (eg. dynamic) 
# and if it is, then updates the DNS record stored on CloudFlare.
#
# Uses curl to be compatible with machines that don't have wget by default (Mac OSX).
#
# Usage
# =====
# 1. Run './cf-ddns.sh'
#
# Optional
# ========
# Follow these steps to run this script every 5 minutes.
# 1. Run 'crontab -e'
# 2. Add this on a new line (modify): 
# 		*/5 * * * * /path/to/the/script/cf-ddns.sh >/dev/null 2>&1
#
# Authors
# =======
# * jfro (initial version)
# * Ross Hosman (modified to use curl and CloudFlare)
# * Dominik Hadl (new API, comments, reorganized)
#
# --------------------------------------

# Your CloudFlare API Token
cftkn="YOUR_API_TOKEN"
# Your CloudFlare account email
cfemail="YOUR_REGISTERED_EMAIL"
# The domain stored on CloudFlare you want to change
cfdomain="YOUR_CLOUDFLARE_MANAGED_DOMAIN"
# The subdomain, or record name of that domain
cfsubdomain="YOUR_CLOUDFLARE_MANAGED_SUBDOMAIN"

# The DNS record ID
#
# See this article for instructions on how the get the ID: 
# https://www.cloudflare.com/docs/client-api.html#s3.3
#
cfzoneid="YOUR_CLOUDFLARE_DNS_RECORD_ID"

# --------------------------------------

# Get the WAN IP
WAN_IP=`curl -s ifconfig.me`

# Get the last saved WAN IP
if [ -f "$HOME/.cf-ddns/wan_ip.txt" ]; then
        OLD_WAN_IP=`cat "$HOME/.cf-ddns/wan_ip.txt"`
else
        echo "No file, need IP"
        OLD_WAN_IP=""

        if [ ! -d "$HOME/.cf-ddns" ]; then
        	mkdir "$HOME/.cf-ddns"
        fi
fi

# Check if it has changed and update if needed
if [ "$WAN_IP" = "$OLD_WAN_IP" ]; then
        echo "IP Unchanged"
else
        echo $WAN_IP > "$HOME/.cf-ddns/wan_ip.txt"
        echo "Updating DNS to $WAN_IP"
		curl -s https://www.cloudflare.com/api_json.html \
		-d "a=rec_edit" \
		-d "tkn=$cftkn" \
		-d "email=$cfemail" \
		-d "z=$cfdomain" \
		-d "name=$cfsubdomain" \
		-d "service_mode=0" \
		-d "ttl=1" \
		-d "type=A" \
		-d "id=$cfzoneid" \
		-d "content=$WAN_IP" > /dev/null
fi

# --------------------------------------