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In this introductory chapter we want to just lay some of the groundwork, for understanding the network infrastructure that Windows Server 2003 is built upon. And I want to start with the look at the NetBIOS Namespace. Even though you won't really need to know this for testing purposes, and even though you might not use this in a Windows 2000 or 2003 only type of network, it is still important in heterogeneous computing network to understand what we're talking about here. What you need to know about a Namespace, any Namespace is that it exists to give names to computer things, network items like network cards or more specifically computers. And the reason why this is significant is because humans like to deal with computers by names. We like to go to sites like yahoo.com rather than have to know an IP address and in chapter 2 we talk all about IP addresses. What you need to know about the NetBIOS Namespace is that it is a Namespace that is flat, in other words there is no hierarchy of domains in the Namespace, just simply a name is given to a network device and it's as simple as that. The other thing you need to know about the NetBIOS Namespace is that every NetBIOS name is 15 characters plus one hexadecimal character and that identifies the service that's running on the network. All NetBIOS names are unique and they are unique because of that 16th character. So we'll take a look at that when we look at a utility called Nbtstat, we will see the NetBIOS register. Also why you might need the NetBIOS names in your network is that they may be needed to support legacy apps or operating systems, for example earlier versions of Windows still rely on NetBIOS. Now, to communicate, computers want numbers so to use NetBIOS names they have to be resolved to IP addresses, typically unless it's a NetBIOS only environment, which would be very, very, rare today. How does that happen? Well one of two ways. You can use either an LM host file, which is a text file that just says here's a name, here's the IP address or you can use a server service in the Windows version called WINS, Windows Internet Name Server service or server but don't be fooled by the Internet part of that name. It is not used on the Internet and it's not used on the Internet because our first bullet point the NetBIOS Namespace is a flat Namespace. So this lays a little bit of the groundwork and I want to actually show you more what I'm talking about. To show you the NetBIOS names that are registered for a given computer you can do this as well. Open up the command prompt and type nbtstat, the Nbtstat utility use it with the N switch, or the N parameter and this shows you all of the names that your computer has registered. So at boot up time, names associated with this computer are registered on the network. How does that happen if you don't have a WIN server, they're just broadcast out there and the broadcast says hey! anybody on the subnet, if anybody's using this name let me know, so I won't register it but no answered back, so it was okay in this case. BEANLAKE1, which is the name of the computer, the WORKGROUP, which is the name of the group, notice these two names look similar and I just said there can only be one NetBIOS name for any given Namespace because it's a flat Namespace, Why are there two Bean Lakes registered? Well it's because of this 16th character that makes them unique. This type, UNIQUE meaning an individual network card or computer, GROUP means that this computer belongs to a group and this will happen with domains as well. So I'm not in a domain yet but we will in chapter 2 when we join a DNS name space but for now the group name is group. Now that's just a quick way to be aware of the NetBIOS names that are registered by a computing device, even in Windows 2003 environment. The other thing that I mentioned was the LM host file and I'm browsing through Windows Explorer here, and the location of the LM host file is in your Windows directory, the installation directory, the system root directory and then look under the system32 directory and then find drivers and etc, and in this folder there are a couple of files that help resolve names to IP addresses and one of them is called LMHosts. The first time you open this file you might be prompted for an application to open it with, any ASCII text editor will be able to open it just fine, like Notepad is one of the number of ASCII text editors and here it just tells you what the LMHost file is all about. This used to be a little bit more important when we were dealing with NT environment because it was used in NT quite a bit but here is the essence of the LMHost file. Here's an IP address and here is the name that is resolved to that IP address. So if you want to, these are all comments, they've got pound sign before them, so if you want to add things to the LMHost file, you type in the information here at the bottom of the file, you can just use this file. So again we just lay the groundwork here in this chapter, we want to be aware of the NetBIOS Namespace, look at some ways that it can be resolved, through an LMHost file or more commonly through a WIN server. How do you get your WIN server information? Through the properties of your TCP/IP addresses and we'll look at that in the TCP/IP section. So you'll see this come back and just we'll mention it from time to time so I want to lay the groundwork here.