Someone asked me how to adjust DSCP value on Windows 2003 server. Of course, you can adjust it in local policy’s network template, but I want to introduce another way.

Firstly, you need to install QoS Packet Scheduler services:

Secondly, you might want to download Windows 2003 resource kit and install TCMON by double clicking tcmon.bat

After you start TCMON.exe, you will find the network interface cards name were listed in the combo box, and the list box should be empty by default. If you see the list is not empty, you might already have flow installed by other applications.

You can add a new flow by clicking “add” button, in the parameter tab, just choose “best effort” under service type panel and uncheck other settings. Under advanced parameters tab, check “override DSCP (DCLASS)” and set the value you want. Under Filter tab, you can set different rules to fit your requirement. If you just want to apply the setting to every network traffic packet, please also create a filter with all default settings. Save it and get back to the main window of TCMON, you should be able to find the new flow has been added.

Now you can run your network application to send/receive packets, you can use ethereal /network monitor or any other tools to check the DSCP value of every packet.

Note, if you close TCMON or restart the machine, the DSCP value will be reset. If you need a tool which can run in background and/or auto start, you might want to write it by yourself. Traffic Control Functions can help you to finish the tool.