Solution

Disable the client's network adapter or disconnect the client's network cable. Ping the IP address of the client from another host to check whether there is a host using the same IP address.

If a ping response is received, the IP address has been manually configured on a host. Execute the dhcp server forbidden-ip command on the DHCP server to exclude the IP address from dynamic allocation.

Enable the network adapter or connect the network cable. Release the IP address and obtain another one on the client. For example, to release the IP address and obtain another one on a Windows XP DHCP client:

1. In a Windows environment, select Start > Run. Enter cmd in the dialog box, and click OK to enter the command line interface.

2. Enter ipconfig/release to relinquish the IP address.

3. Enter ipconfig/renew to obtain another IP address.