I have already wrote how to upgrade port speed under Red Hat or Debian Linux. If you would like to upgrade or downgrade port speed under Windows 2003 server just use following guideline.
By default, most dedicated hosting service provider or your network administrator will provide you (hook you to) 10Mbps connection to Internet. If you would like to upgrade either of your port speeds to 100mbps or 1000mbps, you need to ask your network administrator to make port upgrade at network switch level. Once the network admin changed the port speed you need to make changes to Windows 2003 networking.
Please note that information outlined here also applies to Windows XP and other version of Windows operating systems.
=> Click on Start button => Open Control Panel => Select Network connections => Select the network interface (if you have multiple network cards) i.e. Local area connection #1. => Right click Properties => Click on Configure button => The driver properties window should open on screen. => Select the Advanced tab. => Select Link Speed & Duplex from the property list. => Select the Value tab to the right and set the port speed you are upgrading to WITH full duplex:
For 10 MBS Select: 10Mbps/Full
For 100 MBS Select: 100Mbps/Full
For 1000 MBS Select: Auto
=> Select the OK Button. => Save the changes and close, the network related windows. It may take upto 1 minute for new settings depend upon switch and traffic.