By default, when a Windows XP DHCP client is unable to contact the DHCP server or default gateway, they receive an APIPA (Automatic Private IP Addressing) IP address, until connectivity is restored.
Windows XP offers the ability to configure an IP address, Subnet mask, Default gateway, Preferred DNS server, Alternate DNS server, Preferred WINS server, and Alternate WINS server which will be used when the DHCP server cannot be contacted.
To configure this Alternate Configuration:
1. Use Start / Network Connections, right-click the network adapter that will receive the Alternate Configuration, and press Properties.
2. Select Internet Protocol (TCP/IP) and press the Properties button.
3. Make sure that Obtain an IP address automatically is checked on the General tab.
4. Select the Alternate Configuration tab.
5. Check User configured.
6. Configure the TCP/IP settings to be used when you cannot contact a DHCP server.
7. Press OK and OK.