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We conclude chapter 6 here with a discussion of a new feature, a new utility available with Server 2003 known as the dependency walker. And the dependency walker can be launched by it's executable, in fact that's what we'll do and the executable's called depends.exe. This goes above and beyond the functionality of the dependencies tab that we saw in the previous module when investigating our services. And this walks a dependency hierarchy for a given service but also for programs that we specify. It builds this tree diagram. So this lets us pinpoint exactly every file and every module that needs to be present for a given program to run or a given service to start. So this is most useful to help us diagnose and resolve problems related to services and applications having missing files, or mismatched computer types or those kinds of things where a program relies on something that just isn't there or is of the wrong type. So let's investigate how to use this thing by going to the start menu, hitting run and then typing depends in the run dialog box in the open section. That opens up the dependency walker. Now probably one of the first things that you want to do is from the options menu you want to configure handled file extensions, so this especially for programs will specify which extensions you want the dependency walker to be active for. So one of the common file extensions would be like .exe, click on add there. Other common ones you might want to consider adding are APIs for Application Programming Interfaces, and add and dll and add and we'll just say OK for right now. Now what's really cool about this is that the dependency walker now for those file extensions that we configured, will add a menu item to our right click menu when we're browsing around through Explorer. So let's take one of the services that we looked at in a previous module, which was the distributed file system service. Now that service is launched by its executable dfssvc.exe and that is kept in the system root folder, in this case Windows, select system32 folder, dfssvc.exe there we go. I right click on it, I choose view dependencies and now in the dependency walker the dependency hierarchy tree is built. Now with this dependency walker you see all of the modules and all of the files that the DFS service relies on, relies on the kernel to launch successfully. And so getting a lot of workable information usually requires collaboration with some one who has a bit of a programming background, but as administrator we want to know what the dependency walker is, what it's for and how we can use the tool to gather this type of information. Making use of the information is not necessarily our first objective here. There is one last service related utility I'd like you to be familiar with come exam time and it is the command line utility service configuration or sc.exe We can use the SC utility for the testing and debugging the services that are necessary for a functional server. It can be used to configure a service to retrieve status of the service; it can also be used to stop and start a service. It is especially valuable when an administrator has to remotely start and stop a utility especially from the command line, maybe in a low bandwidth environment. Like another utility netsh or netshell utility it's not really so much use of switches but in one of several contexts, the contexts are then used with context specific switches. So there's a lot of syntax to think about with SC. It's not important to memorize the syntax but rather to identify what is this utility used for. What is it used for? To configure and gather information about the services in use on a computer. Some examples of this would be SC start, which would start a service, SC stop which would stop a service and then the service name. You could also enter SC and then config, which will configure service and then specify the service name. This is just again overview of how to use service configuration, overview of how to use the dependency walker to help you troubleshoot and manage your services that are vital to network operation.