Linksys WRVS4400N Manual page 43

After entering the necessary information, the Router will advise the DDNS Service of
your current WAN (Internet) IP address whenever this address changes. If using TZO,
you should NOT use the TZO software to perform this "IP address update".
Connect button: When DDNS is enabled, the Connect button is displayed. Use this
button to manually update your IP address information on the DDNS server. The Status
area on this screen also updates.
Click the Save Settings button to save the network settings or click the Cancel Changes
button to undo your changes.