How do I release and renew my computer's IP address?

It may be necessary to release and renew your computer’s IP address after configuring a modem or router or if you can no longer access the Internet.

These instructions assume that your computer's TCP/IP settings are set to obtain an IP address automatically (or using DHCP). To force the computer to renew its IP address, either restart your computer or follow the steps below.

For Windows Vista:

1. Open the Start menu and in the Start Search field, type cmd and press Enter. 
2. The Command Prompt window opens. At the blinking cursor, type ipconfig /release and press Enter.
   If you get a message saying "The requested operation requires elevation:"
3. • Close the Command Prompt window.
   • From the Start menu, open All Programs → Accessories.
   • Right-click on Command Prompt and select Run as administrator. 
   • If a User Account Control dialog box appears, click Continue. 
   • Return to Step 2 above.
4. Now type ipconfig /renew and press Enter.

For Windows XP and 2000:

1. From the Start menu, select Run.
2. Type cmd in the Open field, and then click OK.
3. The Command Prompt window opens. At the blinking cursor, type ipconfig /release and press Enter.
4. Now type ipconifg /renew and press Enter.

For Windows Me and 98:

1. From the Start menu, select Run.
2. Type command in the Open field, and then click OK.
3. The MS-DOS Prompt window opens. At the blinking cursor, type winipcfg /release and press Enter.
4. Now type winipcfg /renew and press Enter.

For Mac OS X 10.5 (Leopard):

1. From the Dock or Apple menu, open System Preferences and then Network.
2. Select your connection method, normally Ethernet for a wired connection or AirPort for a wireless connection.
3. Click the Advanced button on the right pane.
4. Make sure the TCP/IP tab is selected, and then click the Renew DHCP Lease button.
5. Click OK and then Apply.

For Mac OS X 10.4 and 10.3:

1. From the Dock or Apple menu, open System Preferences and then Network.
2. From the Show drop-down menu, select your connection method, normally Built-in Ethernet for a wired connection or AirPort for a wireless connection.
3. Make sure the TCP/IP tab is selected, click the Renew DHCP Lease button, and then click  Apply Now.