Windows XP: How to change your network card’s usage priority

If you happen to have a desktop or laptop which has more than one network adapter, one for the LAN and the other connected to your modem, Windows may mess up it’s internal routing table and try to reach google.com over your LAN connection.

This mini-howto provides some information about changing your network card’s order (or priority). This is handy to specify on which network connection your programs will go. Be sure to backup on paper everything you change so you can come back to safe defaults in case of troubles.

Open a Run box using the Start menu and clicking Run (this may be quickly reached by typing Win+R, that is, holding the Windows key between Ctrl and Alt and pressing R), and execute ncpa.cpl — which is a quick shortcut to your “Networking neighborhood” ’s Propreties.

Select advanced in the top menu, and choose Advanced Settings. The first list in the first tab (Adapters and bindings) is the actual order of your physical network adapters. That is,   everytime you or some program tries to connect over a network card, it will go thru all those cards (unless specified otherwise) until the destination is reached. You can re-arrange the order by selecting one of the adapters in the list, and clicking on the arrow buttons on the right side. Click OK when done.

If you happen to have disabled the Printing Spooler service, clicking Ok will warn you about not being able to completly do the changes, which is false to some point. Since our objective is to move around the priority of the adapters, this part is actually done BEFORE the error message popping up, so the changes (at least, the parts we’re interested in) are actually done. You may discard the error message and click on Cancel in the adapters window– note that it doesn’t cancel what we’ve done, you may verify if you wish so.

You may try to test your network at this point, but it didn’t made the trick for me. You may ALSO have to change the TCP/IP Routes priority too. Follow these steps, and do not fool around too much, since we can really funk up the system’s networking in there! You’ve been warned

Still in the Network Connections window (the ncpa.cpl window), right click and choose propreties on every network connections than you think it causes troubles. Or, to reverse the problem around, choose Properties on the network connection you want to push up to the first one being used at all times.

In the General tab, select the TCP/IP option in the list and click on Propreties (shortcut: you can also simply double-click on TCP/IP), and click on the Advanced button in the lower part of the General tab. In the IP Parameters Tab, uncheck “Automatic Metric” and in the textbox below, enter a numeric value between 1 and 9999. This value is actually important and deals with the TCP/IP routing priority of the Windows networking. By putting a small value, this network connection will be used first, and with a large value this will be used as later as possible, depending of the others connection’s Metric value.

In other words, your connection attempt will use every connection (shown as connected or not disabled in the Networking window) ordered by the metric value specified here.