Machine Names and DNS Entries

DNS entries created for DHCP clients last eight hours, and they are assigned/updated based on the MAC address they were first created for. This means when changing the MAC address for a DDNS entry you would need to either wait eight hours for it to take effect, or perform a DHCP release on the old client, for the new client to be assigned the DNS entry.

For Windows, open a command window and type: ipconfig /release