Microsoft has set up the networking infrastructure in Windows Vista in such a manner that it requires only minimal user interaction, especially when the operating system has to interact with a Dynamic Host Configuration Protocol (DHCP) server.
DHCP is designed to take the user out of the equation of assigning an Internet Protocol (IP) address to a certain computer connected to a network, and making the process completely automatic. In order to set up or change the configuration of the TCP/IP settings make your way via the Start button, Control Panel, Network and Internet, Network and Sharing Center, and then Manage network connections.
In the Network Connections window, you will be able the see one or more connections depending on your system, right-click the connection you want to manage and select Properties from the contextual menu that will be displayed. Under the Networking tab, select either Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol Version 6 (TCP/IPv6) depending on which protocol you use. Most likely, it is IPv4. Make sure that the Obtain an IP address automatically and Obtain an IPv6 address automatically are selected in order to automatically assign the IP addresses to your computers.
Sometimes, however, you might run into problems. The kind that the Network and Sharing Center will not be able to resolve on its own. And you will find that you lost network connectivity. One such example is the deletion of the TCP/IPv4 default gateway address when the network interface IP address for DHCP in Windows Vista is configured via the Netsh command-line tool, with a command prompt such as: "netsh interface ipv4 set address name="Local Area Connection" source=dhcp".
In such a case, you will have to turn to the "Ipconfig" command-line utility in Vista. Enter "cmd" in the Search box under the "Start menu" and then right-click the highlighted result and choose Run as administrator, or press Ctrl + Shift + Enter in order to run command prompt with elevated privileges. There are two commands that you can use, both (in the order illustrated below) explained by Microsoft:
"/release [Adapter] : Sends a DHCPRELEASE message to the DHCP server to release the current DHCP configuration and discard the IP address configuration for either all adapters (if an adapter is not specified) or for a specific adapter if the Adapter parameter is included. This parameter disables TCP/IP for adapters configured to obtain an IP address automatically. To specify an adapter name, type the adapter name that appears when you use ipconfig without parameters.
/renew [Adapter] : Renews DHCP configuration for all adapters (if an adapter is not specified) or for a specific adapter if the Adapter parameter is included. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically. To specify an adapter name, type the adapter name that appears when you use ipconfig without parameters."Microsoft, Windows Vista, TCP/IP, Network, Networking, Tips and Tricks, Knowledgebase, Article