Step-by-step instructions to configure a DDNS using dynu.com.
1 – Register an account on dynu.com
Be sure to use a password you are happy to leave in the router config.
https://dynu.com
Once registered, navigate to Control Panel, DDNS Services:
Click ‘Add’.
Create your domain name of choice.
2 – Login to the Cisco router and configure DDNS
Enable IP Domain Lookup
ip name-server 1.1.1.1
ip name-server 8.8.8.8
ip domain lookup
Configure DDNS updater to run at an interval of 90 seconds.
Be sure to add your chosen domain name and the password used when registering your account to the below config.
To insert a ‘?’ on the router CLI, press “ctrl+v” then “?”.
ip ddns update method dynu.com
HTTP
add http://api.dynu.com/nic/update?hostname=example.loseyourip.com&password=s3cr3tPA55w0rd
remove http://api.dynu.com/nic/update?hostname=example.loseyourip.com&password=s3cr3tPA55w0rd
interval maximum 0 0 1 30
3 – Enable DDNS Updater on Outside Interface
interface Gi0/0
ip ddns update hostname example.loseyourip.com
ip ddns update dynu.com
Troubleshoot
If you encounter any issues, try “debug ip ddns update” and check through the logs.
Ensure any ACLs/ZBFW have been configured to permit the DDNS traffic. (UDP/53 and TCP/80).