Bash script to update dynamic zone hosted at Hurricane Electric.
Step 1: Create a dynamic zone with TTL 300 using the HE web interface.
Step 2: Set a key to update the dynamic zone (a.k.a password)
Step 3: Change the domain and password parameters on the shell script.
Step 4: Make the script executable
# chmod a+x update-hedns.sh
Step 4: Set up a cronjob to check and update the IP periodically
e.g. hourly
1 * * * * /usr/local/bin/update-hedns.sh >> /dev/null 2>&1