In the days before Windows XP, a corrupted IP installation could often be fixed simply by removing and reinstalling TCP/IP. In most cases, the IP-related files remained intact, but some related Registry keys would be corrupted beyond repair.
You can't uninstall TCP/IP in Windows XP, because there is no Uninstall button for this protocol. According to Microsoft, that is because TCP/IP is an integral part of the operating system, and removing it would cause major problems. You can, however, use the Windows XP command line utility NetShell to reset all IP-related Registry settings to their default values. The result is a brand-new TCP/IP configuration.
The Netsh.exe program is located in the C:\Windows\ System32 directory. To use the program, enter the command "netsh int ip reset filename." You must specify a filename, such as Ipstuff.txt. After Netsh .exe runs, the file will contain a detailed log of the Registry keys that were modified.
If you routinely move your laptop between two locations, you should know about Windows XP's alternate IP configuration feature. If one location (your office, for example) requires a fixed IP address configuration, you can specify the office IP address, gateway address, and DNS server address information in the Alternate Configuration tab of the TCP/IP Properties page.
When your computer starts, it automatically attempts to obtain an address from a DHCP server. If no DHCP server is found, Windows uses the alternate IP address information. If a DHCP server is found (as would happen on a home LAN with an Internet gateway device), the system uses the DHCP-provided address instead.
Windows XP has a new feature called Network Bridge, which lets you connect disparate media types into one seamless LAN. For example, if you have a network PC connected to a LAN, cable modem, or DSL modem via Ethernet, you can create a bridge between the Ethernet connection and your PC's FireWire connection.
When you connect a laptop to the desktop via FireWire, the Network Bridge provides an IP connection to the laptop, even though the laptop isn't connected directly into the network. To create a bridge, select two connections in the Network Connections control panel, then right-click on them and select Bridge Connections.
If you are bridging an Ethernet connection to a FireWire connection, you must manually set the IP address information (including IP address, gateway address, and DNS server address) on the FireWire-connected laptop, even if the LAN is configured to assign IP addresses automatically using a DHCP server. If you frequently connect the same laptop to the same desktop, you can use the alternate IP address configuration feature to set the IP address to use for the FireWire connection.
Windows XP includes built-in drivers for several popular wireless LAN cards. In most cases, you can simply pop in a wireless card and use it with no configuration changes. But the generic Microsoft wireless LAN driver doesn't provide access to some manufacturer-specific features, like manual channel selection and proprietary authentication schemes.
If you need access to these features, you'll need to install the driver provided with your wireless card. But be aware that if you install a manufacturer-specific driver, you may lose the ability to connect to any wireless LAN you may encounter. Whereas Windows XP automatically connects to any new wireless LAN that it sees, some manufacturers' drivers don't let you do this without changing settings (usually the system-specific ID, or SSID) in the LAN card driver.