# Using an alternate IP configuration in Windows XP

*2007-03-26*

> Configure Windows XP to use DHCP with a static IP fallback, making it easier to move a laptop between home and work networks.

I noticed Windows XP’s **Alternate Configuration** feature while using SP2. It allows one network adapter to obtain its IP settings from a DHCP server and fall back to a predefined static configuration if no DHCP server is available.

This is especially useful for a laptop that moves between different networks. I’d been thinking of writing a helper tool to do this!

To set it up:

1. Right-click **My Network Places** and select **Properties**.
2. Right-click your network connection and select **Properties**.
3. Select **Internet Protocol (TCP/IP)** and click **Properties**.
4. On the **General** tab, select **Obtain an IP address automatically**.
5. Open the **Alternate Configuration** tab and select **User configured**. Enter the static IP address, subnet mask, and any required gateway and DNS settings for the other network.
6. Click **OK** to save the settings and close the properties dialogs.

In my case, DHCP supplies the settings at home, while the alternate configuration contains the static settings I use at work.