One of the most important skills IT professionals need to master is troubleshooting networking connectivity: that is, computers establishing a connection with one another. A number of components facilitate this communication, and many times, IT professionals end up troubleshooting issues with these components.
This chapter discusses the software components that allow a computer to network with other computers as well as the troubleshooting issues that could arise while configuring a network. In this chapter, you find out how to connect to networking resources and how to troubleshoot when you cannot make the connection.
Understanding Networking Components
When setting up a network, you must have the appropriate hardware and software in place to allow systems to communicate with one another. Because this chapter focuses on the software components needed to allow Windows to network, you can assume that you have all the necessary hardware in place. You have a hub or switch, at least two computers and network cards to go in the computers, and the appropriate cabling to connect the network cards to the hub/switch is already connected. After all the hardware is in place, consider what you have to do at the operating system level to get these computers talking. Not only do you need the physical hardware in place but you also need to load software components, such as a network card driver, protocol, service, and client software. These are the four major software components required to network.
When building your network, it is important to identify the four major software components that allow a Windows OS to function in a networking environment:
Network adapter driver
Network client
Protocol
Services
I discuss each component in detail in the sections that follow. Be sure you are comfortable with them for the A+ Exams!
Network adapter driver
The network adapter driver is the physical network card inserted into one of the computer’s expansion bus slots, connected as a USB device, or integrated into the system board. The network card is responsible for sending information onto the network and receiving information from the network.
Before purchasing a network card, you have to figure out what type of card you need. To do this, open the computer (for more information on safety procedures, refer to Book 1, Chapter 3), look at the expansion buses supported in your system, and then identify which has an empty slot. For example, if you have a PCI slot and a PCIe, you can choose between a PCI or a PCIe network adapter. Typically, you would opt for the PCIe network adapter because of the performance benefits of PCIe devices over PCI devices.
A USB network adapter is a popular choice today. If you go with a USB network adapter, you won’t need to open the computer — simply plug the USB adapter into an available USB port.
After you install the network card into the empty expansion slot or USB port, you install the driver for that card within the OS. Installing the network card driver is the first major step to networking a system because the driver software allows the OS to communicate with the physical device — in this case, the network card. Figure 3-1 shows how the driver sits between the OS and the physical hardware, controlling communication between the two.
FIGURE 3-1: The relationship between the OS and a hardware device is controlled by the device driver.
Installing a network adapter in Windows
After you insert the network card into the computer, Plug and Play will kick in when the computer is powered on. If the OS has the device driver for the card, it will load the driver automatically, and you will see the device listed in Device Manager.
If the OS doesn’t have the driver, it will either prompt you for the driver (and then you need to supply the manufacturer’s CD for the network card), or the device will be listed in Device Manager as an unknown device. To update the driver for the device in Windows, go to Device Manager to update the driver. The following steps demonstrate how to update a driver in Windows:
Click Start, right-click Computer, and choose Properties in Windows 7, or right-click the Start icon and choose System in Windows 8.1.
In the System Properties dialog box, click the Device Manager link on the left.
The Device Manager appears.
Within Device Manager, expand Network adapters and right-click your network card.
To update the driver, choose Update Driver, as shown inFigure 3-2.
If your network card isn’t listed in the Network Adapters section of Device Manager, look under the Unknown Devices category. If the device is in the Unknown Devices category, right-click it there and choose Update Driver.
The Update Driver Wizard starts.
Select Install from a List and then click Next.
Select Don’t Search, I Will Choose the Driver to Install; then click Next.
Select the manufacturer of your network card (on the left) and then choose the model of your network card (on the right). Click Next.
If your network card model isn’t in the list, click the Have Disk button so that you can supply the location of the driver.
After the driver is copied, click Finish.
FIGURE 3-2: Updating a network card driver in Windows.
Understanding network connections
After you load the network card driver, Windows creates an icon that represents the network card; this icon is called a network connection. If you have multiple network cards installed, you have multiple network connections — one representing each network card.
The purpose of the network connection icon is to give you a place to configure any network settings responsible for communication between the network card and the local area network (LAN). For example, if you want to ensure that TCP/IP is used by your network card, right-click the local area connection and choose Properties. In the Properties of the network connection, you can add or configure networking components, such as TCP/IP.
To view your network connections in Windows, choose Start ⇒ Control Panel (in Windows 7) or right-click the Start icon and choose Control Panel if using Windows 8.1. Once in the Control Panel, choose Network and Internet ⇒ Network and Sharing Center.
The Network and Sharing center is the main screen for viewing or changing your network settings. To see the different network connections, choose the Change Adapter Settings link on the left side of the screen. You’ll see a window that displays your network connection icons, as shown in Figure 3-3. Each of these network connections is there because of a network card driver being installed for your network interfaces.
FIGURE 3-3: Viewing local area connection in Windows.
When you right-click the local area connection icon, its contextual menu gives you a number of tasks. Here are tasks that you might use when you troubleshoot networking issues:
Disable: Temporarily cut off communication to and from the network. This is a quicker solution than physically removing the network card from the computer.
Enable: This choice is a toggle of Disable when you disable a card. After you troubleshoot your network (hopefully, you fix the problem) and you need to re-enable the network connection, choose Enable.
Status: Display a dialog box showing how long the connection has been up and running and also the speed of the connection. On the Support Page tab, you can view your IP (Internet protocol) address information and MAC (Media Access Control) address.
Diagnose: Have Windows perform maintenance on the connection by performing tasks such as renewing your IP address, flushing the ARP (Address Resolution Protocol) cache, and flushing the NetBIOS and domain name system (DNS) resolver cache.
Rename: Give the connection a more meaningful name. For example, I renamed the LAN for the network card connected to the Internet to Internet Connection.
Properties: Open the Properties dialog box for your LAN connection. In the Properties dialog box, you can modify the network setup of the network card. For example, you can add or remove network protocols or change their configuration.
After you make sure that the correct hardware settings are applied to the network adapter, your next step is to connect to a network resource. Unfortunately, you cannot connect to a network resource until you have the appropriate network client running. The following section describes the purpose of the network client.
Network client
In essence, a network client is no different than a client or customer in the real world. A client in the real world visits your company because you provide some sort of service. Say you run a tailor shop. The customer is a client of the tailoring service.
Computer networks work the same way. On your computers, you must run a client for the type of service you are requesting on the network. For example, if a company runs the older Novell NetWare as the server OS, you must load a client that will connect your computer to the Novell server. Or, if you want to connect to a Windows server, you have to load a Microsoft client on your system.
The Windows OSes come with the Client for Microsoft Networks already installed so that you can automatically connect to a Windows network.
To return to my tailor shop example, say that your client asked your service to tailor some pants. When the client finally receives the mended pants, that client is pleased — however, the pants have to be dry-cleaned before they are used. Unfortunately, your business doesn’t offer dry-cleaning services, so your client has to request that service from a third party. The point is that your client can be a client of tailoring and a client of dry cleaning at the same time. There is no rule that says you can be a client of only one particular service at a time.
To install a network client for Microsoft networks in Windows, follow these steps:
Locate the network connections:
Windows 8.1: Right-click the Start icon and then choose Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center ⇒ Change Adapter Settings.
Windows 7/Vista: Click Start ⇒ Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center, and then click the Change Adapter Settings link on the left.
Right-click the network connection, which should appear as Ethernet (Windows 8.1) or local area connection (Windows 7), and then choose Properties.
If it isn’t already active, click the General tab.
Verify that Client for Microsoft Networks appears in the list of components and has a check mark beside it, as shown inFigure 3-4.
If the check box is not selected, select the Client for Microsoft Networks check box to enable the Microsoft networking client. If the Client for Microsoft Networks is not in the list, install it: Click the Install button and choose Client from the Network Component Type dialog box. Click Add, choose Client For Microsoft Networks, and then click OK.
FIGURE 3-4: Verify that Client for Microsoft Networks is installed.
At this point, you should have your network card and its driver installed, and you should also have installed the appropriate client. Unfortunately, you still cannot communicate with someone on the network because you still have to install the appropriate protocol. In the following section, I talk about the purpose of protocols and what common protocols are running on networks today.
Protocols
Protocols are languages used to hold a conversation on a network. Your system can have a network card installed and have the proper client running, but if it is not speaking the same language (um, protocol) as the remote system, the two systems cannot hold a conversation. Back to the tailor shop example: You are now ready to service your clients, but you have a teeny problem. The first client who walks into your store and requests service speaks French, but you speak only English. To solve this problem, you and your client must speak a common language — and it doesn’t matter what that language is, as long as you both can speak it.
There are a few things to look for when choosing which protocol to install, but the bottom line is that all computers on the network must have the same protocol installed — a common denominator to allow all individuals to participate in a conversation. In the following sections, I discuss a few different protocols that you might encounter when working with networks. Be sure you are familiar with these protocols when you take the A+ Certification Exams.
NetBEUI
NetBIOS Extended User Interface (NetBEUI) was originally developed by IBM to be used on small networks (fewer than ten computers). Microsoft implemented NetBEUI in the different Windows OSes for the same purpose — small networks — because it is a nonroutable protocol, meaning that it cannot leave the network. Because many companies have large networks spanning some form of wide area network (WAN) link and containing routers to connect different networks, this protocol is impractical in those environments and for environments that want to connect to the Internet.
In the past, you would use NetBEUI if you had a small number of computers that needed to be networked in a workgroup-type environment. You wanted to get this network up and running without the hassle of having to configure all kinds of settings. This is the benefit of NetBEUI: There is no configuration — it just works! In today’s networking environments, though, seeing NetBEUI on any major network is unlikely.
TCP/IP
Transmission Control Protocol/Internet Protocol (TCP/IP) is the hot protocol on the market these days because it is the protocol of the Internet and Internet-based technologies. TCP/IP has become the protocol of choice for Windows, Linux, and Novell networks because of its ability to communicate in heterogeneous environments. The bottom line is this: It doesn’t matter what kind of OS you are running — if you’re running TCP/IP, you can communicate globally.
TCP/IP is a protocol suite. Protocol suites are like application suites in the sense that there is more than one protocol in the group. For example, if you purchase the Microsoft Office suite, you purchase an entire group of applications, or an entire suite of applications. TCP/IP is a group of protocols that make up the protocol suite, and some of these protocols are used day in and day out. For example, adding the TCP/IP protocol suite to your computer means that you have a Telnet application for running applications from another computer, and you have an FTP application for downloading files from another computer.
Because configuring TCP/IP is such a big topic, I devote an entire section of this chapter, “The TCP/IP Protocol,” to it.
TCP/IP is a routable protocol, and NetBEUI is a nonroutable protocol.
Services
One of the most forgotten networking components is the service, which is a piece of software running on the computer that provides certain functionality. An example of a service that runs on the computer is file and printer sharing, which is the service that provides files, folders, and printers to other systems on the network.
Going back to the tailor shop example: Before you can have clients, you must have first made the decision to offer the service. If you do not offer the service, there is no reason for customers to want to communicate with you.
So, on a network, someone has to offer the service, but not everyone needs to. For example, a small company with five Windows machines might have only the machine with the printer connected to it providing the File and Printer Sharing service. The other four Windows computers connect to it by installing Client for Microsoft Networks and ensuring that they are using the same protocol. There is no reason for them to have the service installed because they are offering nothing to the network.
Windows servers usually run at least two services by default:
File sharing services: Allow the server to share files with other users on the network.
Printer sharing services: Allow a printer to be used by multiple users on the network. You don’t need to purchase a separate printer for each user on the network, which is a real cost cutter!
File and Printer Sharing services were the original purpose in life for servers and networks, but the number of services that can be added to these systems has grown over the years to include mail services, web services, FTP services, name resolution services, and many more.
The TCP/IP Protocol
Since the dramatic growth of the Internet, TCP/IP has become the preferred protocol on networks today. TCP/IP is the common protocol on all desktops — including Windows, Linux, and Mac systems — allowing all these different OSes to communicate over a common protocol. It doesn’t matter what OS you run or what kind of network you have: As long as you are running a common protocol such as TCP/IP, you can access resources across any platform.
TCP/IP is installed by default with every major OS (Windows, OS X, and Linux). When configuring TCP/IP on these systems, three major settings need to be configured to allow the computer to communicate with other computers on different networks or the Internet:
IP address
Subnet mask
Default gateway
To troubleshoot communication across TCP/IP, you need to understand the types of settings that need configuring. In the sections that follow, you look at how to configure TCP/IP and at some utilities to help you troubleshoot the protocol.
IP address
The IP address is a 32-bit number that is unique to your computer. No two systems can have the same IP address. An IP address is similar to the address of your home, which is the method by which other people send mail to you. An IP address works the same way on a TCP/IP network: You assign the number to your computer, and it is the method other computers use to send information to your computer.
An IP address is made up of four sets of numbers separated by periods: dotted decimal notation format. Here’s an example
131.107.2.200
Each of the four sets of numbers represents an octet (because each octet represents 8 bits of data).
The IP address comprises a network ID and a host ID:
Network ID: This unique number is used only by your network and is also the same for all computers on the same network.
For example, in the IP address 131.107.2.200, the first two octets (131.107) make up the network ID. So if computer A with an IP address of 131.107.2.200 talks to computer B with an IP address of 131.107.3.5, you can assume that the two computers are on the same network because 131.107.x.y is the network ID for both computers.
Host ID: This portion uniquely identifies a computer on the network.
For example, in the IP address 131.107.2.200, the last two octets (2.200) make up the host ID. Only one computer on the 131.107.x.y network can have the host ID of 2.200.
The network ID is not always the first two octets of the IP address. So how do you know which octets make up the network ID and which octets make up the host ID portion of the IP address? The class of IP address you have dictates which numbers correspond to which IDs. The three major classes of IP addresses are Class A, Class B, and Class C. The different IP address classes support a different total number of workstations on the network. For example, a Class A network (a network using Class A addresses) supports as many as to 16,777,214 network devices, a Class B network supports 65,534 network devices, and a Class C network supports only 254 network devices.
Class A networks use the first octet as their network ID and the remaining three octets as the host ID. A Class B network uses the first two octets for the network ID and the last two octets as the host ID. A Class C network uses the first three octets as the network ID and the last octet for the host ID.
How do you know what class IP address you have? Look at the first octet. If it has a value between 1 and 127, it’s a Class A IP address; if it has a value between 128 and 191, it’s a Class B IP address; and if it has a value between 192 and 223, it’s a Class C IP address. Table 3-1 summarizes IP address classes.
In the Number of Hosts column, two numbers are missing. For example, a Class C address could have 256 possible addresses, numbered 0 through 255. However, you are not allowed to use 0 because it is reserved for the network ID. Also, you are not allowed to use the 255 because it is the broadcast address, which is how systems send data to every computer on the network. To summarize, with each address class, you lose two addresses because of the network ID and the broadcast address.
It is important to note that no system or device can start with an IP address of 127 in the first octet. This is because it is illegal for a system on the network to have an IP address that starts with 127 as it is a reserved address. Any address starting with 127 is illegal because this address is reserved for the loopback address, which is an address that always refers to the TCP/IP software stack that initialized on your system. Typically, the loopback address is referred to as 127.0.0.1, but you could use any address that starts with 127. For example, you could issue the following command in a command prompt to test that TCP/IP is functioning properly on your system:
Ping 127.0.0.1
No matter what your IP address is, the loopback address is a constant that you can use to verify that your system is running correctly.
Here’s an IP address example: Computer A has an IP address of 194.12.11.10, and it initiates communication with computer B, whose IP address is 194.13.11.9. Are the two workstations on the same network? Looking at the first octet, you can see that the number 194 is a Class C address, which means that the first three octets make up the network ID, and the last octet is the host ID. Because there is a difference in the first three octets (which is the network ID), these two computers are on different networks.
Identifying whether the computer you are trying to communicate with is on your network could be important when troubleshooting communications. If the computer you are trying to communicate with is not on your network, the problem could be with your computer, the remote computer, or the router. This means you have more places to look for the cause of the problem.
Subnet mask versus CIDR
Another way to tell whether your computer is on the same network as the computer you are trying to communicate with is to look at the subnet mask. The subnet mask is what your computer uses to determine whether the network device it is trying to communicate with is on the same network. The subnet mask helps the system determine the network ID portion of the IP address by comparing the subnet mask against the IP address. If there is a 255 in the subnet mask, the corresponding octet in the IP address is part of the network ID. After the network ID is known, any systems that have the same network ID are considered to be on the same network; otherwise, they would have a different network ID.
Different classes of IP addresses are associated with different default subnet masks. For example, a Class A address has a default subnet mask of 255.0.0.0, a Class B address has a default subnet mask of 255.255.0.0, and a Class C address has a default subnet mask of 255.255.255.0. Looking at the subnet masks, any octet with the value of 255 means that the corresponding octet in the IP address is part of the network ID.
To put this all together, Table 3-2 shows an example of two computers and their IP address configurations.
Using this example, computer A tries to connect to computer B. The first thing that computer A does is compare its IP address with its own subnet mask to determine what octets make up the network ID. Here it sees that the first octet is the network ID because the subset mask has the number 255 in only the first octet. Then computer A compares its subnet mask with the IP address of computer B (the remote computer it is trying to communicate with) and identifies that the network IDs of computer A and computer B are different — the two computers are on different networks.
When computer A realizes that the remote computer it is trying to communicate with (computer B) is on a different network, it starts to panic because it doesn’t have the capability to send the information to the other computer. Computers can pass information directly to other computers only if both systems are on the same network. So what happens? This is where the default gateway fits into the story.
Before moving on to the default gateway, I first want to talk about CIDR notation. It is common for IT professionals to document an IP address, but instead of specifying the subnet mask, they use CIDR notation to specify it instead. With CIDR notation, the number of bits in the subnet masks that have been enabled (set to a 1 state) are specified. For example, a subnet mask of 255.0.0.0 has the first 8 bits enabled (set to 1), while the last 24 bits are set to 0. This means the CIDR notation is /8. To document a class A IP address that has a subnet mask of 255.0.0.0 using CIDR notation would be something like this: 24.56.7.22/8. Class B addresses have a CIDR notation of /16 (subnet mask of 255.255.0.0), and class C addresses have a CIDR notation of /24 (subnet mask of 255.255.255.0).
Default gateway
When information has to be forwarded from a computer on one network to a computer on another network, a special network device called a router must be used. The router has a table that lists all the networks it knows about and the network ID associated with each of those networks. When the router receives information destined for a particular IP address, it checks its table of network IDs for a match. If a match is found, it delivers the information to the appropriate network.
How does the information get to the router so that it can be forwarded? Looking at the example from Table 3-2 in the previous section, computer A has information for computer B, and computer A realizes that computer B sits on a different network. At this point, computer A looks at its default gateway, which is the address of the router that will forward the information on to computer B’s network. Note that the address of the default gateway must use the same network ID as the local system. The default gateway is a TCP/IP option configured on each workstation. Typically, all computers on the same network point to the same router.
When you are comfortable with the concepts of an IP address, subnet mask, and default gateway, you are ready to configure these options on a Windows OS, which I cover in the next section.
Configuring TCP/IP in Windows
To configure TCP/IP on a Windows system, access your local area connection properties and configure the TCP/IP protocol. Be aware that all Microsoft OSes today have TCP/IP installed by default. You simply need to configure the IP address on the system. To configure TCP/IP with static addresses on a Windows system, follow these steps:
Locate the network connections:
Windows 8: Right-click the Start icon and then choose Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center ⇒ Change Adapter Settings.
Windows 7/Vista: Click Start ⇒ Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center, and then click the Change Adapter Settings link on the left.
Right-click your network connection, which appears as local area connection (Windows 7) or Ethernet (Windows 8.1), and then choose Properties.
Select Internet Protocol Version 4 (TCP/IPv4) and then choose Properties.
To assign a static address, select Use the Following IP Address (as shown inFigure 3-5) and then type your computer’s IP address, subnet mask, and default gateway in the corresponding text boxes.
Type the address of your DNS server in the Preferred DNS Server text box.
To know what to enter as the IP address of your DNS server, consult the network administrator or maybe even the network architects. Whoever has designed the network knows the IP address of the DNS server. (DNS is covered in more detail in the section “DNS,” later in this chapter.)
Click OK and then OK again.
FIGURE 3-5: Configuring TCP/IP on a Windows client.
To communicate with systems off the network, your computer will need an IP address, a subnet mask, and a default gateway configured. To communicate with systems on the network, you need only an IP address and subnet mask configured.
Configuring TCP/IP en masse using DHCP
If you are the network administrator of a large network, you do not want to run around to 400 workstations and configure an IP address, a subnet mask, and a default gateway on each computer. Not only is this time-consuming to initially set up, but it also becomes a nightmare to manage because of all the potential for human error. I have spent my days running around to each computer on the network, a sheet of paper in my hands, making sure that each computer is configured properly, and I can tell you that it is not fun!
Today’s network OSes support Dynamic Host Configuration Protocol (DHCP), which is a standard that allows the network administrator to tell the DHCP server a range of IP addresses that it is allowed to give out, along with the other TCP/IP options such as a subnet mask and default gateway. When the DHCP server is configured to give out the addresses, the desktop computers automatically request an IP address from the server when they start up, and the server hands them all the IP address information. This means that the network administrator does not have to run around to each computer individually to configure TCP/IP — which, in the long run, saves time and money.
The steps to configure a Windows system to obtain an IP address from a DHCP server are very similar to actually assigning the IP address manually.
To configure a Windows client for DHCP, follow these steps:
Locate the network connections:
Windows 8.1: Right-click the Start icon and then choose Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center ⇒ Change Adapter Settings.
Windows 7/Vista: Click Start ⇒ Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center, and then click the Change Adapter Settings link on the left.
Right-click your network connection, which appears as local area connection (Windows 7) or Ethernet (Windows 8.1), and then choose Properties.
Select Internet Protocol Version 4 (TCP/IPv4) and then choose Properties.
On the General tab, select the Obtain an IP Address Automatically option, as shown inFigure 3-6, to enable this system to be a DHCP client.
Click OK and then OK again to close the network connections dialog box.
When configuring your system to use DHCP, you will notice an Alternate Configuration tab within your TCP/IP settings (see Figure 3-6). The alternate IP address is a setting that allows you to assign a static IP address that you want the Windows system to use in case a DHCP server is not available to give an IP address to the client.
Here’s an example of where you can use the alternate IP address: If you are connecting a laptop at work, the laptop receives an IP address from the company DHCP server, but when you use the laptop at home, you may not have a DHCP server available. In that case, you can configure the system with an alternate address. If you do not configure the system for an alternate address and no DHCP server is available, you will receive an APIPA address. To learn more about APIPA addresses, read about special addresses next.
Special addresses
When looking at IP addresses, you need to be familiar with a few special addresses when troubleshooting systems and preparing for your A+ Certification Exams!
Loopback address
The first special address to always remember is the loopback address. The loopback address is any address that begins with 127. Most IT professionals know the loopback address as 127.0.0.1, but it is really any address that starts with 127.
The loopback address is used to verify that the TCP/IP software is running fine on your system. In order to verify that TCP/IP is installed and running on your system, you can ping the address of 127.0.0.1. If you get a reply, TCP/IP is running fine on your system. Otherwise, you need to re-install TCP/IP.
Public addresses
Most of the IP address ranges that exist are known as public addresses, which means that if your system is using one of the IP addresses, it is allowed to access the Internet using that address.
A few addresses are not considered public addresses, but are known as private addresses.
Private IP addresses
A private IP address is a type of IP address that is designed for local network communication only, and not for surfing the Internet. As mentioned, these addresses can be used to network machines on your LAN but cannot be used to surf the Internet because the addresses are for private use only.
The three private IP address ranges are
10.0.0.0 to 10.255.255.255
172.16.0.0 to 172.31.255.255
192.168.0.0 to 192.168.255.255
It is interesting to note that the third range of 192.168.0.0 to 192.168.255.255 is what most home networks use because the home router is using that network range. I say this is interesting because you can surf the Internet at home using this address, but yet I say that private addresses cannot be used for Internet access. Huh? This doesn’t make sense! To surf the Internet using a private IP address, you use a technology called Network Address Translation (NAT) that is built into the home router. More on NAT later in this chapter!
Automatic Private IP Addressing (APIPA)
If a DHCP server isn’t available and your Windows clients are configured to obtain an IP address automatically, will they receive an IP address? Yes, because Windows operating systems support the Automatic Private IP Addressing (APIPA) feature. APIPA allows the client to self-assign an IP address if the DHCP server does not respond to the DHCP request. The address that the client self-assigns is within the 169.254.x.y network range. The system will also configure itself with a subnet mask of 255.255.0.0 but will not configure the default gateway entry. This means that if the DHCP server is down and your network clients boot up, they will all have an address in the 169.254.x.y range and will be able to communicate with one another. Because they are not configured for a default gateway entry, they will not be able to communicate with systems off the network or with the Internet.
When troubleshooting networking connectivity, use the ipconfig command to view the TCP/IP settings on a client. If the IP address is 169.254.x.y, that means the client cannot communicate with the DHCP server. Make sure that the client is connected to the network correctly and then verify that the DHCP server is functioning!
Network Address Translation
Home routers use the Network Address Translation (NAT) technology. The router is a NAT device, and a NAT device has two network cards: one connected to the Internet and one connected to the inside network. Your client systems use the NAT device (the home router) as their default gateway, so they send all outbound Internet traffic to the NAT device.
The NAT device converts the private address being used as the source IP address of the packet to the public address assigned to the WAN interface on the NAT device. As a result, the packet looks like it is coming from the WAN port of the NAT device, which is actually using a valid public address. When the reply comes back, the NAT device translates the address back to the private address and then sends the packet to the client system inside the network. This is completely transparent to the clients on the network.
One benefit of NAT is that you can share the one public IP address assigned by your ISP to the WAN port on the router, thus allowing you to have multiple computers on your home network surfing at the same time. Another benefit is a security benefit: That is, your internal network structure is hidden from the outside world. From the Internet’s point of view, the system surfing the web is the NAT router. If nefarious folks decide to attack that address, they are attacking the NAT device — and not the IP of a machine on your network.
Proxy settings
Some companies use what is called a proxy server, which implements NAT along with the capabilities to authenticate the individual trying to surf the Internet and authorize the website they are trying to access. Proxy servers are a great way for companies to monitor Internet usage and control what protocols and sites users can visit. For example, if the company decides that employees are spending too much time on websites such as Facebook during work hours, the company can have the proxy administrator disable access to that site.
In order to block access to websites, the company has to configure the employee’s web browser to navigate through the proxy server to get to the Internet. The following steps show how to configure Internet Explorer on a Windows system to use a proxy server:
Launch Internet Explorer with the quick launch button in the Taskbar.
If you don’t see Internet Explorer in the Taskbar, you can find it in the Start menu.
Once you are in Internet Explorer, click the Tools button (gear icon in the top-right corner) and choose Internet Options.
Click the Connections tab.
At the bottom of the screen in the Local Area Network (LAN) Settings area, click the LAN Settings button.
At the bottom of the dialog box, in the Proxy Server section, select the Use a Proxy Server for Your LAN check box.
Type the IP address of the proxy server in the Address field.
Click OK, and click OK again to exit.
IPv4 versus IPv6
All the IP address information you have read about in this chapter is in regard to IP version 4 (IPv4). You now know that IPv4 addresses are 32-bit values that take a dotted-decimal notation such as 192.168.1.33.
Two major flaws exist with IPv4:
Running out of IP addresses: Partly because only 32 bits are in an IPv4 address and because of the growth of the Internet, we are running out of IP addresses.
No security: IPv4 was designed to allow communication and was not focused on making sure that communication was secure.
With the new IPv6 protocol, the IP addresses are 128 bits long in hopes that we will never run out of addresses. The entire format for the IP addresses was also changed in IPv6. The addresses are now in hex values and look similar to the following address:
fe80:0000:042b:9853:1ff2:4cd3:2ff3:5cd2
The IPv6 protocol is designed with security in mind, and security protocols are built right into IPv6 itself. For example, IPv6 has IPSec capabilities, which allow traffic to be encrypted.
Understanding Name Resolution
To communicate with another computer across a TCP/IP network, you have to know the IP address of the computer you are trying to communicate with. This is unrealistic, considering that you are probably not too interested in trying to memorize all the IP addresses of the different websites you visit every day.
When running a TCP/IP network, you assign a friendly name to each computer and reference each computer by the friendly name instead of using the IP address. This means that instead of using an address like 204.56.78.6 to connect to Bob’s computer, you would use a friendly name — say, bob.
The two types of names to understand when troubleshooting TCP/IP networks are
Computer names (also known as NetBIOS names)
Fully qualified domain names (FQDNs)
NetBIOS names
In the Windows world, you access resources on a system by connecting to the computer name of the system. As an administrator, you assign a computer name to each computer on the network. The computer name (NetBIOS name) is a friendly name of as many as 15 characters assigned to a computer and used to uniquely identify the computer on the network. Users can then connect to the computer by the computer name or by the IP address — and people find it much easier to remember the computer name!
Changing the computer name in Windows
Changing your computer name in Windows is a common task, and is fairly straightforward with today’s Windows OSes.
To change your computer name in Windows, follow these steps:
Choose Start ⇒ Control Panel (in Windows 7) or right-click the Start icon in Windows 8.1, and then choose Control Panel.
In the Control Panel, choose System and Security and then choose System.
You can see the computer name toward the bottom of the screen.
To change the computer name, click the Change Settings link that appears on the right next to the computer name.
Click the Change button.
The Computer Name Changes dialog box appears, allowing you to type a new computer name, as shown in Figure 3-7.
When changing your computer name, notice that you can set the workgroup as well. A workgroup is the term given to a logical grouping of computers. When users browse the network, they may choose a workgroup, such as Accounting, and then they will see any systems that are a part of the Accounting workgroup. To place your system in a particular workgroup, simply type the name of the workgroup in the text box.
Type a new computer name and workgroup for your system and then choose OK to close out all the dialog boxes.
Reboot the system.
The computer name does not take effect until you reboot the system.
FIGURE 3-7: Changing your computer name in Windows.
WINS
When you network in a Microsoft environment, you connect to other computers by using those computers’ names. These computer names must be converted to IP addresses for communication to happen in a TCP/IP network. For example, you may want to connect to Bob’s computer, so you connect to \\bob through the Run command on the Start menu. When you try to connect, \\bob has to be converted to an IP address for the computer to be able to look for it. The process of converting a name from one format to another is name resolution. In this example, the computer name is being converted to an IP address, which is known as NetBIOS name resolution.
With NetBIOS name resolution, before your computer tries to connect to another system, it sends a query to a Windows Internet Naming System (WINS) server, asking the server this: “Hi there, Mr. WINS server. I am trying to connect to a computer named bob — do you have an IP address for this computer?” The WINS server holds a database of NetBIOS names and matching IP addresses: the WINS database. Think of this database as having two columns: one for the computer name (NetBIOS name) and one for the matching IP address. Upon receiving the question, the WINS server checks the database for the computer named bob and then returns its IP address to the client who asked for it. Then the client can connect by using the IP address for bob.
For a Windows system to send a query to the WINS server, you must ensure that you configure the WINS server setting within the TCP/IP properties of the client system. Configuring the Windows client for a WINS server directs the client to the server that it must register its name and IP address with and also whom to send name resolution queries to.
Before configuring your clients for WINS, you must be aware of the IP address used by the WINS server. If you do not know this information, consult the network administrator. After you have the IP address of the WINS server, you are ready to configure the WINS clients. To configure a Windows system as a WINS client, follow these steps:
Locate the network connections:
Windows 8.1: Right-click the Start icon and then choose Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center ⇒ Change Adapter Settings.
Windows 7/Vista: Click Start ⇒ Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center and then click the Change Adapter Settings link on the left.
Right-click your network connection, which appears as local area connection (Windows 7) or Ethernet (Windows 8.1), and then choose Properties.
Select Internet Protocol Version 4 (TCP/IPv4) and then choose Properties.
In the Internet Protocol (TCP/IP) Properties window, click the Advanced button.
Click the WINS tab.
Click the Add button to add the IP address of the WINS server.
Type the IP address of the WINS server and click Add, as shown inFigure 3-8.
Keep clicking OK until you close all dialog boxes.
If you do not have a WINS server but an application you are running requires the use of a NetBIOS name (computer name), you need to use the LMHOSTS file. The LMHOSTS file resides on each computer and is used to resolve, or convert, computer names to IP addresses. This file exists on each system on the network. You simply need to add an entry for the computer name and the corresponding IP address for each system that you want the file to resolve. Figure 3-9 displays a typical LMHOSTS file.
FIGURE 3-9: An example of an LMHOSTS file in Windows.
Windows stores the file in %systemroot%\system32\drivers\etc. In Windows, the folder has an existing LMHOSTS file that you can use as a sample, but it has a .sam extension that needs to be removed because the true LMHOSTS file has no extension.
Fully qualified domain names (FQDNs)
The other type of name that can be assigned to the computer when you are running a TCP/IP network is a host name, or a fully qualified domain name (FQDN). FQDNs are used when you run a TCP/IP-based or Internet-based application, such as FTP, email, or web browser applications. For example, to navigate to my website via your favorite web browser, you would type www.gleneclarke.com — this is an example of an FQDN. An FQDN is an Internet-style name that needs to be converted to an IP address for communication to occur.
The point is that when you use a computer name or an FQDN on a TCP/IP-based network, the names always need to be converted to the actual IP addresses. Again, converting names (either computer names or FQDNs) to IP addresses is name resolution.
There are a few techniques for FQDN resolution, and some are more popular than others. The following sections describe the name resolution techniques and their purposes.
DNS
DNS (Domain Name System) is the desired name resolution technique for resolving (converting) fully qualified domain names to IP addresses. Remember that FQDNs are the names that are used with Internet-based applications, such as email and web browsers. DNS is like a big database of FQDNs and their matching IP addresses. Think of this database as having two columns — one for the FQDN and the other for the IP address.
When you are running Internet or TCP/IP applications and you type in a FQDN, your computer sends a query to the DNS database asking something like this: “I am trying to connect to www.gleneclarke.com. Do you have the IP address that matches this FQDN?” The database looks up the FQDN and returns the IP address to your computer, and your computer then connects to that IP address.
The big question is, where is the database stored? The database is stored on DNS servers. These servers hold the actual records and also where each client computer on your network sends its name queries.
To configure a Windows client to use a DNS server, you add the IP address of the DNS server while configuring TCP/IP. (Refer to the section “Configuring TCP/IP in Windows,” earlier in this chapter.) Notice also that in Windows, the DNS server option is on the same screen as where you assign the IP address for a computer, which shows how critical DNS is to today’s computing! To configure a Windows client to use DNS, follow these steps:
Locate the network connections:
Windows 8.1: Right-click the Start icon and then choose Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center ⇒ Change Adapter Settings.
Windows 7/Vista: Click Start ⇒ Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center and then click the Change Adapter Settings link on the left.
Right-click your network connection, which appears as local area connection (Windows 7) or Ethernet (Windows 8.1), and then choose Properties.
Select Internet Protocol Version 4 (TCP/IPv4) and then choose Properties.
In the TCP/IP Properties dialog box, select the Use the Following DNS Server Addresses option and type the IP address of your DNS server, as shownFigure 3-10.
Click OK twice to close the dialog boxes.
FIGURE 3-10: Configuring a Windows client for DNS.
The HOSTS file
Very similar to the idea of using an LMHOSTS file for NetBIOS name resolution (see “The LMHOSTS file” section, earlier in the chapter), you can use a text file, called the HOSTS file, for host name resolution. The HOSTS file is located in the %systemroot%\system32\drivers\etc folder on Windows systems.
The configuration of the HOSTS file is similar to the configuration of the LMHOSTS file. You simply create two columns — one for the FQDN and the other for the IP address of the system. Separate these columns with a tab. Figure 3-11 shows a sample HOSTS file.
FIGURE 3-11: An example of a HOSTS file used for FQDN resolution.
ARP
Be aware that another layer of resolution needs to happen after your client has the IP address of the system it wants to communicate with. You know that there is a different database for FQDN resolution and computer name resolution: namely, the DNS database stores FQDNs and their IP addresses, and the WINS database stores computer names and associated IP addresses. After the name is converted to the IP address, the IP address then must be resolved to the hardware address burned into the network card. This hardware address assigned to each network card is the MAC address. This means that there has to be a process that converts the IP address to the MAC address, and this process is Address Resolution Protocol (ARP). ARP is an address resolution protocol that converts the IP address to the physical address assigned to the network card.
ARP is a broadcast, or a yell, out on the wire for a particular address. Look at an example of computer A trying to send information to computer B: After computer A has the IP address of computer B (204.56.78.3), computer A yells at the top of its lungs, “Hey, 204.56.78.3! What is your network card’s MAC address?” This yell runs along the network and eventually reaches computer B, which responds with its MAC address. After computer A has the MAC address of computer B, it can then send the data to computer B.
ARP messages are broadcast messages, and broadcast messages do not pass through routers. This does not cause a problem because when you want to communicate with a system on a different network, your system sends the data to the default gateway, or router, and then the router sends the data off the network by ARPing the router on the destination network. In this example, your system communicates with the router, so it would ARP the router, not the destination system!
DNS and the HOSTS file resolve FQDNs to IP addresses. WINS and the LMHOSTS file resolve computer names to IP addresses.
Looking at Protocols and Ports
When you run networking applications on a computer, each of those applications runs on a unique port address. The port address is a number that data is sent to in order for it to reach the application. For example, if you are running a web server on a system, the web server software uses port 80, but the email server software uses a totally different port number — 25 (and Minecraft uses port 25565!). Ports are the reason why our systems can receive different types of network traffic and the computer does not confuse the types — email traffic is received on port 25, while web traffic is received on port 80.
TCP versus UDP
Along with the port, you should understand that most network communication uses either the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). If a network application uses TCP, it is considered to be connection based — meaning that a system must introduce itself first to the other application and establish a connection before sending any data. Also TCP-based applications verify that any data sent is actually received by the other party; if not, the sending system will retransmit the data. A UDP-based application is considered connectionless because it does not establish a connection to another system and just sends the data off to the target system without any official introductions (connections). Also, UDP does not verify that the data reaches the destination like TCP does.
Common ports
The A+ Exams expect you to know the port numbers of common TCP/IP protocols:
FTP: The FTP protocol uses TCP port 21 to transfer files across the Internet.
SSH: The SSH protocol is used as a secure remote management protocol that runs on TCP port 22.
Telnet: Telnet uses TCP port 23 to perform remote management of a system with the communication unencrypted. Note that SSH is the secure replacement to Telnet.
SMTP: SMTP is the protocol of the Internet for sending email. SMTP uses TCP port 25.
DNS: DNS is used to resolve FQDNs to IP addresses. DNS uses UDP port 53 for DNS queries.
HTTP: Web pages are delivered to web browsers using the HTTP protocol, which uses TCP port 80.
POP3: The Internet protocol to read email is POP3, which uses TCP port 110.
IMAP: IMAP is a newer protocol for reading email that is designed to replace POP3. IMAP uses TCP port 143 and has more features than POP3, such as being able to filter what messages are downloaded to the client.
HTTPS: HTTPS is used to securely transmit web pages using TCP port 443.
RDP: The Remote Desktop Protocol (RDP) is used to carry screen-shot information and keyboard input across the network when remotely managing a system. RDP uses TCP port 3389.
NetBIOS/NetBT: NetBIOS over TCP/IP is the use of NetBIOS names, such as computer name, and having that computer name used to connect to resources on a TCP/IP network. NetBT uses UDP ports 137-139.
SMB/CIFS: SMB is now known as CIFS and is the file sharing protocol within the Windows environment. SMB/CIFS runs on TCP port 445.
SLP: The service location protocol is a protocol that enables computers and devices on the network to locate a service without any previous configuration on the client. SLP uses UDP port 427.
AFP: The Apple Filing Protocol is a file sharing protocol for OS X and uses TCP port 548.
You are also expected to know the purpose of some common TCP/IP protocols. The following list outlines TCP/IP protocols to know for the A+ Exams:
DHCP: The Dynamic Host Configuration Protocol (DHCP) is a protocol that is designed to give IP addresses out to network devices.
DNS: The Domain Name System (DNS) is a name resolution protocol that converts fully qualified domain names (such as www.gleneclarke.com) to IP addresses.
LDAP: The Lightweight Directory Access Protocol (LDAP) is the Internet protocol for accessing a directory service.
SNMP: The Simple Network Management Protocol (SNMP) is a protocol that allows you to remotely manage a device.
SMB/CIFS: The Server Message Blocks (SMB) protocol is the underlying protocol for allowing Microsoft systems to share network resources.
SSH: The Secure Shell (SSH) protocol is a secure replacement to the Telnet protocol. SSH can encrypt and authenticate network communications.
AFP: The Apple Filing Protocol is the file sharing protocol for OS X that allows Mac systems to share files with one another.
NNTP: The network news transfer protocol is used to transmit news articles between a news server and an NNTP news client.
SFTP: The Secure FTP (SFTP) protocol is the secure replacement to the FTP protocol and is used to secure communications related to file transfer.
Troubleshooting with TCP/IP Utilities
After you have TCP/IP installed and configured and you have your TCP/IP network running, you need to be able to troubleshoot the network. When problems arise on a Windows network, you can use some of the following commands to do your troubleshooting:
IPCONFIG/ifconfig
PING
TRACERT/traceroute
NBTSTAT
NETSTAT
PATHPING
NSLOOKUP
NET commands
The following sections discuss these popular TCP/IP utilities that are used to troubleshoot TCP/IP connectivity.
IPCONFIG/ifconfig
On Windows systems, you can run the ipconfig (IP configuration) utility, which shows you the current TCP/IP configuration of the Windows desktop, such as the IP address, subnet mask, and default gateway. If the computer is a DHCP client, ipconfig identifies the server that has given the IP address and also shows how long the IP address will be used by the client. Table 3-3 shows some of the switches supported by the utility ipconfig.exe.
Shows a list of switches supported by ipconfig.exe and a brief description of each switch
/all
Shows all TCP/IP information — for example, DHCP lease period and the DNS server
/release
Releases the current IP address information assigned by the DHCP server
/renew
Requests new IP address information from the DHCP server
/displaydns
Displays the DNS resolver cache which stores recent results from DNS queries
/flushdns
Clears the DNS resolver cache
For example, to use the ipconfig utility and view just the basic TCP/IP settings, you type the following at a command prompt:
ipconfig
But to view all the TCP/IP settings, such as your MAC address or the IP address of your DNS server, DHCP server, and WINS server, use the ipconfig/all command. You might also view when your lease time is up for the address you have been assigned when you use the /all switch on ipconfig.
Before leaving the topic of viewing your IP address settings, I want to add the point that on a Linux system, you use the ifconfig command to view your TCP/IP settings.
Lab 3-1 gives you practice working with the ipconfig command. You can find Lab 3-1 on the companion website at www.dummies.com/go/aplusaio.
PING
One of the most popular TCP/IP utilities is the ping.exe utility. Ping (Packet Internet Groper) is used to test whether your computer can communicate with a remote network device. If the ping test is successful, you get a ping response from the remote device; if it is not successful, the response will time out. The general syntax for using the ping utility is ping <IP address>, the IP address being the IP address of the network device you are testing.
When troubleshooting TCP/IP communication problems, it is important to understand the steps to find exactly where the problem occurs. Is the problem in the computer you are using, in the computer you are trying to connect to, or in the default gateway?
Table 3-4 lists the order in which to ping each network device when trying to figure out at what stage the TCP/IP communication is failing.
This IP address is the loopback address. It always tests your own workstation’s TCP/IP software to ensure that it has loaded.
IP address of your computer
After you get a response from loopback, ping the IP address that has been physically assigned to your network card. To find out what IP address is assigned to your network card, use ipconfig.exe.
IP address of default gateway
If you get a response from your network card’s IP address, ping the IP address of the default gateway. If you don’t know the IP address of your default gateway, run ipconfig.exe to view the address of the default gateway. Remember that the default gateway is the router, which is responsible for passing information on to other networks. If you are having trouble communicating with the router, you can’t communicate with any devices off the network.
IP address of remote computer
After verifying that the default gateway is not the problem, if you know the IP address of the computer you wish to talk to (and chances are you don’t because you are not the person who assigns the address to that computer), you can try pinging it. If you get a timeout at this step, you know that the computer you are trying to communicate with is the problem.
When you’re troubleshooting a system that doesn’t have Internet access, use the ipconfig utility to view the default gateway of the system; then ping the default gateway.
You also need to know that ping –t allows you to do a continuous ping, meaning that until you stop pinging with a Ctrl+C command (CTRL+C is a common keystroke in most OSes to stop a command), you will continue to ping the system indefinitely. Also know that if you want the ping utility to do name resolution, add –a to the command.
Lab 3-2 gives you practice changing your TCP/IP settings and working with the ping command. Lab 3-3 allows you to test your TCP/IP communication. Labs 3-2 and 3-3 can be found on the companion website at www.dummies.com/go/aplusaio.
TRACERT/traceroute
The ping utility is probably the most used TCP/IP utility, and rightfully so. The ping utility is a very useful utility for troubleshooting communication problems, but the ping utility tells you only whether your computer has communicated with the remote hosts; it does not tell you what path the information took. This is where the trace route (tracert.exe) utility is useful. It is similar to the ping utility in the sense that responses are sent back to you if communication is established. The difference is that tracert.exe sends a response from every network it hits on the way, not just a response from the final destination. So tracert.exe shows you the path the information takes and also the number of networks between your computer and the computer you are talking to.
The trace route utility uses the following syntax (note the space after tracert):
tracert <IP address or DNS name>
It should be noted that to use tracert functionality on a Linux system, the command is traceroute, and not tracert. Also remember that Linux is case-sensitive and as a result commands such as traceroute, ping, and netstat are in lowercase characters.
NBTSTAT
Another popular network troubleshooting utility is nbtstat, which is used to troubleshoot NetBIOS name resolution. (Remember that discussion? If not, look back to the “NetBIOS names” section.) nbtstat stands for NetBIOS over TCP/IP Statistics. When your system resolves a computer name to an IP address, it stores that information in memory (the NetBIOS name cache) so that the next time the name needs to be converted to an IP address the request is resolved from cache instead of broadcasting or querying a WINS server. If you want to verify that the entry is in cache, use the nbtstat utility.
There are a number of uses for the NBTSTAT utility, so there are quite a few switches for the command. Some of the most useful switches are listed in Table 3-5.
Shows a list of switches supported by nbtstat and a brief description of each switch.
-c
Displays the contents of the NBTSTAT cache. This cache shows the computer names and matching IP addresses that have been resolved recently.
-A <ip address>
Displays the list of NetBIOS names used by the IP address typed with the —A. The listing also indicates what types of services the system is running. Note that the —A is uppercase and has a space after it and before the IP address.
-n
Displays the NetBIOS names used by the local system.
-r
Lists which addresses have been resolved through WINS.
To use the nbtstat command, type something like the following at a command prompt:
nbtstat –A 192.168.1.200
NETSTAT
The netstat command line utility (lowercase in Linux) is used to troubleshoot TCP/IP connections. If you use the netstat command by itself, it displays a list of connections that your system has with remote systems and the associated ports.
Like nbtstat, netstat supports a number of switches to help you get the most information possible out of the command. Table 3-6 lists some of the more popular netstat switches.
Shows a list of switches supported by netstat and a brief description of each switch.
-a
Displays all connections that your system has but also all listening ports. A port is what an application uses as an endpoint of communication. For example, applications such as Internet Explorer use a port, and that port is where a web server sends the data so that the data reaches Internet Explorer.
-o
Displays the process ID of the application that opened the port. You can use this information with the tasklist command to track down the application that opened the port. You can then use the taskkill command to terminate the program that opened the port.
-p <protocol>
Shows the connections for the protocol provided to the switch. For example, you could use netstat —p TCP to view all the TCP connections. In this example, you will not see the UDP connections.
An example usage of the netstat command is as follows:
netstat –a -o
PATHPING
pathping is a newer command line utility to the Windows world that allows you to ping a destination, and — like the tracert command — you get a list of hops (routers) from the source to the destination. After the list of hops is determined, pathping sends a number of messages to each hop to calculate statistics on each hop, such as the number of lost packets.
NSLOOKUP
nslookup is a TCP/IP utility used to query DNS and to troubleshoot problems associated with DNS. With nslookup, you can query for a specific type of record, such as email server records (MX records) if you want to know the mail servers for a particular company. Take a look at a few nslookup commands.
The preceding command queries DNS and reports back to you the IP address for the server at www.gleneclarke.com. To find the mail servers for gleneclarke.com, you would type the following commands in a command prompt:
nslookup set type=mx gleneclarke.com
In the previous example, Windows will report to you the entries from DNS that have an MX record type, which are the entries in DNS that reference the email servers for gleneclarke.com.
NET commands
Windows has a number of different networking commands that you can use to perform tasks such as create user account, modify group membership, and map network drives, to name a few.
net user
The net user command is used to view or manage user accounts on the system. When you go to a command prompt and type
net user
this command shows a list of user accounts that exist on the system. To create a user account, you can expand on the command by typing
net user aplusguy P@ssw0rd /add
This command creates a user named aplusguy with a password of P@ssw0rd.
net localgroup
The net localgroup command is used to manage membership to a specific group. If you want to add a user to the administrators group, you would type the following command:
net localgroup administrators aplusguy /add
net view
You can also view a list of domains or workgroups on the network by using the net view command. The following shows a listing of domains:
net view /domain
From this list of domains, you can then view a list of servers in a particular domain by using the net view command as well. The following command is asking to view a list of systems in the glensworld domain:
net view /domain:glensworld
From the list of servers in the domain, you can then potentially view a list of shared folders on one of those systems by typing
net view \\server1
net use
Don’t confuse the net user command with the net use command. net user is used to manage user accounts, and net use is used to map network drives. For example, if you want to create a J: drive on your system that references the shared folder called data on a server called Server1, you would type
net use j: \\server1\data
These are just a few examples of popular networking tasks that can be performed by using the net commands in the Windows OS. To read more about what the net command can do in Windows, use the net /? command.
NETDOM
Another common Windows command line tool that you can use is the netdom command. You can use netdom to perform a number of Active Directory–related tasks such as join a computer to the domain, remove a computer from the domain, or reset the secure channel for computer accounts.
For example, to use netdom to join a computer to the domain, use the following command:
In this case, the current computer is going to be joined to the DCATT domain using the administrator account.
Troubleshooting network issues
Now that you understand some of the commands used to troubleshoot networking problems, I take a look at some common networking issues that arise from time to time.
The following are some common issues that you may need to troubleshoot; you definitely need to know these for the A+ Exams:
No connectivity: If you have no connectivity to a network, you want to always check the physical connections first and then verify your network configuration, such as the IP configuration.
APIPA address/link local address: If you have an IP address of 169.254.x.y, you are having trouble obtaining an IP address from the DHCP server. You need to verify that the client is connected to the network properly and then check the DHCP server.
Limited connectivity: If you are connected to the network and experience limited connectivity, you should verify the IP settings such as the default gateway and the DNS server setting. Also verify that the router is connected to the Internet.
Local connectivity: If you experience local connectivity, only then double-check that the system has a default gateway configured and that the router has a connection to the Internet.
Intermittent connectivity: Intermittent connectivity issues are hard to troubleshoot. Verify that you do not have a problem with the cable, and check for devices that could be causing interference with your network (especially wireless networks).
IP conflict: If you have a duplicate IP address, you will not be able to network. Be sure that the IP address you are using is unique.
Slow transfer speeds: If you are experiencing slow transfer speeds, check the card settings and the settings on the router to see whether you can find a reason that the network devices would be using a slow transfer rate.
Low RF signal: If you have a low RF signal on a wireless network, you may need to go into the router and increase the power level of the signal.
SSID not found: If you are not able to locate the SSID for the wireless network you are trying to join, ensure that the wireless router is broadcasting the SSID.
Troubleshooting with hardware tools
When troubleshooting network communication issues, you typically will find the problem is with logical issues, whether IP address configuration problems or name resolution problems such as DNS. Sometimes physical issues, such as cabling, are the cause of problems with the network. The following are some hardware tools that are often used to troubleshoot cabling issues:
Cable tester: A cable tester is a hardware device that is connected to both ends of the cable and is used to inform you if a signal can be sent from one end and received on the other. Cable testers are used to verify that the cable has been created, or crimped, properly.
Loopback plug: A loopback plug is a device that you can connect to communication equipment to ensure that the port on the communication equipment is working properly.
Punchdown tool: A punchdown tool, shown in Figure 3-12, is used to connect the twisted pair cable to a patch panel or to secure the cable to the back of the wall jack.
Tone generator and probe: A tone generator and probe is used to locate a specific cable in a mess of cables.
Wire strippers: Wire strippers can be their own device or are part of the crimper, which is described next. Wire strippers are used to remove the outer shell of the cable to get access to the wire in the cable.
Crimper: A crimper, shown in Figure 3-12, is a tool that is used to secure the connector to the end of the cable (for example, the RJ-45 connector to the end of the CAT 6 cable).
Wireless locator: A wireless locator is used to scan and identify wireless network and activity around you. This can be useful when troubleshooting wireless problems. Once a wireless network has been found, the wireless locator displays information about the wireless network such as the SSID, signal quality, MAC address, and the channel ID.
FIGURE 3-12: Punchdown tool (left) and crimper (right).
Sharing File System Resources
In this section, I discuss how to set up the Windows OS for sharing network resources. I begin with a discussion of some of the core options that must be set to network within a Windows OS.
Every Windows computer must have a computer name to participate in a Windows network, and each computer name must be unique on the network to properly address a specific computer. To review the steps to change your computer’s name, take a look at the section, “Changing the computer name in Windows,” earlier in the chapter.
User-level access control
Current versions of Windows operating systems use a type of access control known as user level access control. User-level access control means that when you share a resource out onto the network, you actually assign permissions to particular users. If someone wants access to the share, his or her user account has to have been given permissions to the share, and the user must log in with that particular account.
Enabling File and Printer Sharing in Windows
Now that you understand the two levels of access control, you are ready to allow your Windows machines to share resources on the network. First, you must ensure that File and Printer Sharing Services are installed and that File and Printer Sharing is enabled. Then you can start sharing folders and printers.
All Windows OSes have File and Printer Sharing enabled by default. To verify that File and Printer Sharing is enabled within these operating systems, perform the following steps:
Locate the network connections:
Windows 8.1: Right-click the Start icon and then choose Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center ⇒ Change Adapter Settings.
Windows 7/Vista: Click Start ⇒ Control Panel ⇒ Network and Internet ⇒ Network and Sharing Center and then click the Change Adapter Settings link on the left.
Right-click your network connection, which appears as local area connection (Windows 7) or Ethernet (Windows 8.1), and then choose Properties.
Select the File and Printer Sharing for Microsoft Networks check box, as shown inFigure 3-13, and then click OK.
When this check box is selected, File and Printer Sharing is enabled, and you’re finished. If File and Printer Sharing for Microsoft Networks wasn’t listed, you need to install it first, so keep reading.
If File and Printer Sharing isn’t listed, click the Install button to install the service.
Choose Service in the Component Type dialog box and then choose File and Printer Sharing for Microsoft Networks. Then click OK to close all the dialog boxes.
FIGURE 3-13: Verifying that File and Printer Sharing is installed on Windows.
Creating shared folders
When a user on the network wants to access a file on another system, he must connect to a share on that system. Shares are a way to publish the folder on your system for other users on the network so that they can access the files in that folder. If you have not shared any resources, there is no reason for anyone to want to connect to your computer — it would be like giving someone the key to a locked but empty room.
You can share only folders or printers; you cannot actually share a file specifically. To allow users to access a file from across the network, you have to place the file in a folder and then share that folder.
Sharing a folder
To share a folder on a Windows network, you typically must supply certain information such as the name of the share, permissions, and any caching settings you want (shown in Figure 3-14).
Regardless of the version of the Windows operating system you are using, the following options are available when you share a folder:
Share Name: You need to give the share a name. This is the name that will be referred to by users who want to connect to the share.
Comment: This is an optional description of the share that displays in Windows when the user views the list of shares in Detail view.
User Limit: You may limit how many users can connect to the share at any given time. This could be useful if you notice that the system is slow after a certain number of users connect. For example, if you’re sharing a CD-ROM, you may notice that access to the CD-ROM slows after six users connect. In this example, you may want to set the user limit to five. Setting the user limit to maximum allowed will configure the user limit for ten users connected to the share at once because Windows desktop OSes can allow only ten connections at a time.
Permissions: Set permissions on the share. You set permissions to control which users can modify data in the share and which ones can simply read information in the share.
Caching: This feature allows the client to store a local copy of data accessed in the share. This could be useful if you want to allow a laptop user to take a copy of the data home and update the data. The modified data could then be synchronized with the content on the server when the user returns to the office.
Notice in Figure 3-14 that I shared the folder named Data. As mentioned earlier, when sharing a folder, you need to set the share permissions. To set the share permissions, click the Permissions button. The default permissions when sharing have changed over the last few versions of Windows. By default, everyone has the read permissions on shared folders.
When you share the folder, you should alter the default permissions to suit your needs. The following steps show you how to adjust these permissions to your liking:
To remove the Everyone group from the permissions list, click the Remove button.
Add specific users to the permissions list by clicking the Add button.
The Select Users or Groups dialog box appears.
Select which user or group is allowed to connect to the share by selecting the user.
You may add multiple users by clicking the first user, holding down the Ctrl key, and clicking additional users.
Click Add to return to the Permissions dialog box.
To set a user’s permissions, select one of the following permissions for that user:
Full Control: Allows a user to read and change the contents of files on the share, to delete files on the share, and to change the share permissions. This permission is not normally assigned to users.
Change: Allows a user to read the contents of files in the share, change the contents of files that exist in the share, and delete files. Users cannot change permissions on the share with the Change permission.
Read: Allows a user or group to read but not modify the content in the shared folder.
Click OK and then click OK again to exit the dialog boxes.
Sharing a folder in Windows
The steps to share a folder on a Windows 7, Windows Vista, or Windows 8.1 system are very similar. Microsoft has tried to simplify managing the security by creating a wizard-style interface to share folders. To share a folder in Windows, follow these steps:
Locate the folder you want to share on your system.
Right-click the folder and choose Share With.
In the File Sharing dialog box, choose the user (or group) you want to share the folder with from the drop-down list; then choose Add.
Choose the Permission Level for the share (shown inFigure 3-15):
Reader: Allows the user or group to read files from the share folder but not make changes to the content of the shared folder
Contributor: Allows the user or group to add a file to the share and modify or delete his/her own files
Co-owner: Gives the user full permission to the share, including modifying and deleting any files in the share
Click the Share button.
Click Done.
FIGURE 3-15: Assigning permissions levels in Windows.
Hidden shares
In the Windows world, you can also create hidden shares, which are like normal shares in the sense that users on the network can connect to them. The difference is that hidden shares are not advertised — you can’t find them by browsing through the shared folder list on a server. Users will connect to the hidden share by typing the universal naming convention (UNC) in the Run command or by mapping a drive, which you can read about in the “Connecting to Shares” section.
To create a hidden share, use the steps for creating a normal share (see the section “Creating shared folders,” earlier in this chapter). However, when you type a share name in the Share Name text box, you create the hidden share by appending a dollar sign ($) to the end of the share name. For example, if the share name is data and you want it to be a hidden share, you would type data$ in the Share Name text box. The share is then automatically hidden from Windows and users on the network when they browse the servers.
Multiple shares
In Windows, you have the ability to create multiple shares for the same folder. This gives flexibility to the network administrator so that a user can have different permissions for a single folder, depending on what share that user connects to.
On my office network, I implemented multiple shares per shared folder so that during day-to-day activities, not even an administrator can alter files on the server. If an administrator wants to make changes to a folder, he has to connect to the secondary share for that particular folder to have full-control access. This helps prevent a lot of unfortunate mistakes in modifying or deleting files by accident — even network administrators make mistakes! A big rule I follow is “Protect the network from yourself as well!”
Connecting to shares
After you create the shared resource, you can connect to the shared resource from anywhere on the network. There are a number of ways to connect to shared folders; here are a few of the most common:
Browsing network resources
Using a UNC path through the Run command
Mapping a drive through Windows or the net command
The following sections examine each of these methods.
Browsing network resources
To browse network resources in Windows, follow these steps:
Choose the File Explorer button in the Taskbar to browse files on the computer.
Expand Network on the left side of the screen in the folder listing.
You see a list of computers.
Select a computer to see a list of shares on that computer.
You can open any share just by double-clicking it.
You cannot see any hidden shares while browsing network resources. For this reason, it is important to know additional ways to connect to shares, such as through the UNC path.
To browse network resources in Windows Vista, you simply navigate to the network resources by choosing Start ⇒ Network. To view a list of shared resources on a system, double-click the system.
Using a UNC path
You may also connect to a share by using the universal naming convention path. The UNC path is made up of two backslashes (\\), the computer name you want to connect to, one more backslash, and the share name of the folder you want to connect to. The entire syntax looks like this:
\\computername\sharename
You would type this into the Run command, found by clicking the Start button in Windows 7, or on a Windows 8.1 system, you simply type the UNC path while on the Start screen.
Using UNC paths means that you have to be aware of the exact names used for resources on the network, including hidden shares. When you get used to the computer names and share names on the network, you’ll find that the Run command is quicker than waiting to see the list of computers in Network Neighborhood or My Network Places.
Mapping a network drive
You may also connect to shares by mapping drives. If you find that you are constantly connecting to the same resource, you may want to map a drive for the sake of simplicity. The idea of mapping a drive is that, in the end, you have a new drive letter in your “This PC” folder that points to the UNC path of the resource. After the drive is mapped, anytime you want to access the folder on the network, go to “This PC” and double-click the mapped drive.
To map a drive, right-click This PC and then choose Map Network Drive. In the Map Network Drive dialog box, select the letter for the drive you want to create and then type the UNC path to the shared resource into the Path text box. You may also choose the option to re-create this drive mapping the next time you log on so that you do not have to do this again. Figure 3-16 shows the Map Network Drive dialog box.
Lab 3-4 allows you to practice sharing resources and connecting to resources. Lab 3-4 can be found on the companion website at www.dummies.com/go/aplusaio.
Sharing Printer Resources
You share printers in much the same way that you share folders on your system. After you install the printer and configure the settings so that the printer functions properly, it is time to share it.
Sharing a printer in Windows
To share a printer in Windows 7 or Windows 8.1, follow these steps:
Navigate to the Control Panel:
Windows 8.1: Right-click the Start icon and choose Control Panel.
Windows 7/Vista: Click Start ⇒ Control Panel.
In the Control Panel, select Hardware and Sound ⇒ Devices and Printers.
Right-click the printer you want to share and choose Printer Properties.
Click the Sharing tab.
Enable the share by selecting Share This Printer and then give a share name, such as “Canon” or “HP.”
Click OK.
When sharing printers, all the same rules for sharing folders apply as far as the share name goes and how to create hidden shares.
Installing a network printer in Windows
To print, or connect, to a shared printer out on the network, you have to install a network printer on your Windows client that points to the UNC path of the shared printer. A network printer in Windows is a printer installed that refers to a shared printer on the network. When you print to a network printer, the print job is sent to the computer that has the printer installed and prints from the print device connected to that system.
You can install a network printer in a number of ways. The two most popular methods are through the Add a Printer Wizard and through the Run command, depending on the network setup. To install a network printer using the wizard, run the wizard from the Printers folder. The wizard starts up and walks you through connecting to a shared printer. The following section shows you how to install a printer that points to a network location.
In Windows 7, Vista, and Windows 8.1, you install a network printer through the Control Panel by following these steps:
Navigate to the Control Panel:
Windows 8.1: Right-click the Start icon and choose Control Panel.
Windows 7/Vista: Click Start ⇒ Control Panel.
In the Control Panel, select Hardware and Sound ⇒ Devices and Printers.
Click the Add a Printer button on the toolbar.
Select the Add a Network, Wireless, or Bluetooth Printer option.
If the printer appears in the list, choose it. If it does not appear in the list, choose the The Printer That I Want Isn’t Listed option.
Type the UNC path to the printer and click Next.
Click Finish.
Installing a network printer by using Point and Print
One of my favorite ways to install a network printer on a client is by taking advantage of Point and Print within Windows. Point and Print is a feature that copies the printer driver from one system to another as soon as you connect to the printer — no matter how you connect to the printer! What method is quickest to connect to the printer? Using the UNC path in the Run command!
After you type the UNC path of the shared printer you want to connect to, Windows asks whether you want to install the printer on your system. When you choose Yes, a new printer is created in the Printers folder without you having to run through the wizard. The printer driver is automatically copied from the system sharing the printer to your local system.
To install a printer by using Point and Print, follow these steps:
Place your cursor in the Search box in Windows 7, or in Windows 8.1 simply go to the Start screen.
Type\\computername\PrinterShareName, where computername is the name of the system that is sharing the printer, and PrinterShareName is the name of the shared printer.
When asked if you want to install the printer, click Yes.
The printer is now installed and ready to print to.
Networking with Windows
Huge changes have been made to the Windows 7 interface over what you may be used to with the Windows XP interface. Because the A+ Certification Exams expect you to know Windows XP, Windows Vista, and Windows 7, I have dedicated the following sections to the networking interface of Windows 7!
Computer name and workgroup
The first thing you should know is how to change your computer name and workgroup in Windows 7 and Windows 8.1. To change your computer name and workgroup, follow these steps:
Choose Start ⇒ Control Panel (in Windows 7) or right-click on the Start icon in Windows 8.1 and then choose Control Panel.
In the Control Panel, choose System and Security and then choose System.
You can see the computer name toward the bottom of the screen.
To change the computer name, click the Change Settings link that appears on the right, next to the computer name.
Click the Change button.
The Computer Name Changes dialog box appears, allowing you to type a new computer name.
Changing IP settings
To change your TCP/IP settings in Windows 7 and Windows 8.1, follow these steps:
Choose Start ⇒ Control Panel.
Click the Network and Internet link.
Click the Network and Sharing Center link.
The Network and Sharing Center is where you can find all network and firewall options in Windows 7 and Windows 8.1. Get familiar with this window (see Figure 3-17) for the A+ Exams.
In the Network and Sharing Center window, you can get to your LAN connection properties either by clicking the Change Adapter Settings link on the left or by clicking the Local Area Connection link on the right side of the window.
Click the Local Area Connection link for this walk-through.
Click the Properties button to view the network components associated with your local area connection.
Select Internet Protocol Version 4 (TCP/IPv4), and then choose Properties.
Here you can set your IP address, subnet mask, default gateway, and primary DNS server setting. After you set the values, click OK to exit your way back to Windows.
FIGURE 3-17: Network and Sharing Center window in Windows.
Homegroup
A new networking feature that started with Windows 7 and continued with Windows 8.1 is the Homegroup feature. A homegroup in Windows makes it easy to share network resources, such as folders and printers, to other Windows systems in your homegroup. For example, when you share a printer on a system in a homegroup, that printer is automatically installed on any system that joins the homegroup! To create a homegroup in Windows, follow these steps:
Locate Network and Internet:
Windows 8.1: Right-click the Start icon and then choose Control Panel ⇒ Network and Internet.
Windows 7/Vista: Click Start ⇒ Control Panel ⇒ Network and Internet.
Click the Homegroup link.
If you are unable to create a homegroup with the Create a Homegroup button, you most likely must change your network location to Home by clicking the What Is a Network Location link. Click the link and set the location to Home; then the Create a Homegroup Wizard is automatically run.
In the Create a Homegroup Wizard, you are asked what resources should be shared to members of the homegroup (seeFigure 3-18). Click Next.
You are presented with a password that you must write down. This password is needed by anyone who wants to join his or her computer to the homegroup at a later time.
After you have created the homegroup, anyone can join their Windows system to the homegroup by following similar steps. You can also share folders to the Homegroup by right-clicking the folder and choosing Share With ⇒ Homegroup (Read). Or, you could choose Share With ⇒ Homegroup (Read/Write).
If you need to view the homegroup password or leave the homegroup, navigate to the Control Panel, click the Network and Internet link, and then click the Homegroup link. Within the Homegroup Settings window, you can view or print your password, change the homegroup password, leave the homegroup, or modify the sharing settings with the homegroup.
Network profiles
One of the great features of Windows is the network profiles feature. When a user connects to a network such as a wireless network, he or she is prompted as to what type of network it is — a home, work, or public network. The location the users set determines the networking features that are configured. For example, if the user sets the location to work, the firewall on his system could be automatically disabled. Yet if he connects to a wireless network at a hotel and chooses public as the location, you as an administrator can set the public network profile to have a firewall enabled. The benefit of these profiles is that you can configure a system in different ways depending on what profile is selected.
As an example of a network setting that can be set, you can set whether your system will share files with a particular profile. You can also set whether other systems on the network can see your system (known as network discovery) and access your shared folders.
To configure these settings on a per-profile basis, follow these steps:
Locate the Control Panel:
Windows 8.1: Right-click the Start icon and then choose Control Panel.
Windows 7/Vista: Click Start ⇒ Control Panel.
Click the Network and Internet link.
Click the Network and Sharing Center link.
In the Network and Sharing Center window, click the Change Advanced Sharing Settings link on the left side.
The Advanced Sharing Settings appear (see Figure 3-19).
Choose to turn off Network Discovery and File and Printer Sharing for the public profile, but turn them on for the home and work profiles.
Another common network setting you will need to configure is the firewall feature. The Windows firewall is designed to limit what traffic can reach your system. To configure the Windows firewall, follow these steps:
Locate the Control Panel:
Windows 8.1: Right-click the Start icon and then choose Control Panel.
Windows 7/Vista: Click Start ⇒ Control Panel.
Click the Network and Internet link.
Click the Network and Sharing Center link.
Choose Windows Firewall at the lower left of the dialog box.
The firewall can be enabled or disabled for different network profiles by clicking the Turn Windows Firewall On (or Off) link.
Choose whether you want the firewall to be on or off for each of the network profiles.
You can also specify whether you want to be notified if a program is blocked by the firewall.
From time to time, you may need to add exceptions to the firewall; exceptions are selected traffic that you decide to let through the firewall. For example, my son wanted to host his own Minecraft server, so I had to allow the Minecraft traffic to pass through the firewall on his system. To add exceptions to the firewall, click the Allow a Program or Feature through the Firewall link, which is found in the Windows firewall dialog box.
Network card properties
You can configure a number of settings on your network cards. These settings are typically found in the properties of the network card in Device Manager. The following are some common network card settings, also known as properties:
Duplex setting: Within the properties of your network card, you can set whether you want the card to run in full-duplex mode, half-duplex, or autodetect. With full-duplex, the card can send and receive at the same time; with half-duplex, it can only send or receive at one time. If you set the card to autodetect, it will determine the best setting based on the network you connect it to.
Speed: Most cards are multispeed cards and support either 10-Mbps, 100-Mbps, or 1000-Mbps speeds. You can set the speed or again leave it at autodetect.
Wake on LAN: A network card that supports wake on LAN functionality can wake the system out of Sleep mode when it receives a special network message.
PoE: Power over Ethernet (PoE) allows the system to receive power through the Ethernet cable connected to the system.
QoS: Quality of service (QoS) settings allow the traffic to be optimized by limiting bandwidth usage for different types of traffic.
Wireless locator
You can use the Wireless Locator icon found on the right side of the Taskbar. The wireless locator allows you to click the icon on the Taskbar to view a list of wireless networks. To connect to a wireless network, you click the name of the wireless network and you are then prompted for the password for that wireless network. If you type the correct password, you are then granted access.
If a wireless network is present that has the SSID broadcasting disabled, in Windows, you will see an entry for the network in the wireless locator that says Other Network. When you choose Other Network, you must type the name of the SSID. If that is supplied correctly, you are then prompted for the password.
Establishing a connection
Windows allows you to connect to a wealth of other network environments, with the most popular being establishing a secure VPN connection to encrypt data across an untrusted network, or a simple dial-up connection.
You can create a dial-up or VPN connection by clicking the Set Up a New Connection or Network link found in the Network and Sharing Center. The following lists some common types of connections and defines their purpose:
VPN: A virtual private network (VPN) connection is used to connect the IP address of a secure server across the Internet that can encrypt data sent between your system and that server.
Dial-up: A dial-up connection is used to connect to the phone number of a server that can then grant you access to a network over the phone lines. You need to have a modem installed on your system to dial-up to this server.
Wireless: A wireless connection is established by adding a wireless network card to the system.
Wired: A wired connection is created when you add a wired network card to the system.
WWAN: A wireless wide-area network (WWAN) allows access to the Internet through cellphone towers and cellular phones.
Understanding Windows Services
In this section, I introduce you to the concept of a service within the OS and then give an overview of some of the most popular services found in Windows.
A service is a software component within the OS that provides a specific feature. For example, the spooler service provides printing functionality. For you to print, you must have the spooler service running.
There are a number of settings you can configure with services, such as set the service to start automatically when Windows starts, or have it set to manually start, which means that as an administrator you need to start the service. You can also start and stop services in order to troubleshoot that aspect of the operating system — it is like rebooting that part of the operating system!
Restarting a Windows service
To stop, start, or restart a service in Windows, follow these steps:
Locate the Control Panel:
Windows 8.1: Right-click the Start icon and then choose Control Panel.
Windows 7/Vista: Click Start ⇒ Control Panel.
Click the System and Security link.
Click the Administrative Tools link to open the Administrative Tools window.
Double-click the Services icon to launch the Services console.
From the Services console, stop, start, or restart a service by right-clicking the service and then choosing the appropriate command from the contextual menu.
After you know how to stop and start a service, the next step is to understand some of the key services that exist within the Windows OS and what the service offers to the system.
Server service
One of the critical services responsible for the networking of the Windows OS is the Server service, which provides File and Printer Sharing capabilities. So, if you want to print to a printer that is shared on computer A from your system, computer A needs to have the Server service running to allow your system to connect to it.
Workstation service
The Workstation service — the exact opposite of the Server service — is responsible for making the connection to the system running the Server service. Compare this with the example in the preceding section: If you want to print to a printer on computer A, the Workstation service on your computer sends the request to the Server service on computer A.
DHCP Server service
The DHCP Server service handles DHCP server functionality: that is, a server that hands out IP addresses to clients on the network. This service must be running if you want the DHCP server to hand out the IP addresses to network clients. Note: This service exists only on Windows Servers and not on Windows client OSes.
Print Spooler service
As I mention earlier, the Print Spooler service is responsible for the printing environment in Windows. If this service is not running, you cannot print.
Messenger service
The Messenger service is an older service found on older versions of Windows that is responsible for sending and receiving messages within the OS. For example, some features of the OS allow an alert to be sent to the network administrator — and the Messenger service is responsible for the message (alert) being sent. You can send a message to another user on the network at any time via the following command at a command prompt:
Net send BOB “Hi there”
The above command sends a message to a user or computer called BOB, and the message that appears on Bob’s screen reads Hi there. For Bob to receive the message, your computer and Bob’s computer need to have the Messenger service running.
Getting an A+
This chapter discusses the different networking components that allow a Windows OS to function in a networking environment.
Four major networking components are required in Windows networks:
A network client
A network adapter
A common protocol
A service
TCP/IP is the most popular networking protocol used today. When installing TCP/IP, you need to configure the following:
An IP address
A subnet mask
A default gateway
The NetBEUI protocol is a nonroutable protocol used on small networks.
In Microsoft networking environments, to allow users to connect to your hard drive or printer, you must install the File and Printer Sharing service.
You may use the ipconfig command in Windows to view your TCP/IP configuration.
The ping command is used to send test messages to a remote system to verify that communication can take place on that system.
Prep Test
1.What networking component allows you to connect to a Windows Server?
(A) File and Printer Sharing service
(B) Client Service for Netware
(C) TCP/IP
(D) Client for Microsoft Networks
2.There is a shared folder named public on a computer named Server1. What is the syntax to connect to the shared resource via the UNC path?
(A)\\server1\public
(B)\\server1\data
(C)\\data\server1
(D)\server1\\data
3.Which of the following IP addresses has a default subnet mask of 255.255.255.0?
(A)10.45.65.78
(B)132.107.2.34
(C)48.123.45.67
(D)216.83.24.56
4.You would like other people in the office to be able to access the printer that is attached to your Windows 8.1 computer on your small network. Which networking component must you install?
(A) Client for Microsoft Networks
(B) Client Service for Netware
(C) File and Printer Sharing for Microsoft Networks
(D) NetBEUI
5.Which of the following is an example of a Class B IP address?
(A)164.34.56.8
(B)12.45.76.2
(C)202.34.65.32
(D)125.67.6.7
6.What two properties of TCP/IP must be configured to communicate with other hosts on a small, local network?
(A) IP address
(B) DNS server
(C) Default gateway
(D) Subnet mask
7.A user tries to connect to a shared resource called data on server1 by using the UNC path \\server1\data but is unsuccessful. The user knows the IP address of server1 and can successfully ping it. What is the problem?
(A) The user should use \\data\server1.
(B) The client computer is not configured to query the WINS server.
(C) The client computer is not configured to query the DNS server.
(D) The user needs to install TCP/IP.
8.Which utility allows you to see the path that information may take when communicating with a remote system?
(A)ipconfig.exe
(B)tracert.exe
(C)winipcfg.exe
(D)arp.exe
9.Which of the following TCP/IP settings are required to connect to the Internet? (Choose all that apply.)
(A) IP address
(B) WINS
(C) Subnet mask
(D) Default gateway
10.Which resolution technique is used to resolve the IP address to a MAC address?
(A) DNS
(B) WINS
(C) ARP
(D)ipconfig.exe
11.Which utility allows you to see the IP address information on a Windows 7 computer?
(A)netstat.exe
(B)ipconfig.exe
(C)tracert.exe
(D)arp.exe
12.Which service is responsible for automatically assigning IP address information to each computer on the network?
(A) DNS
(B) WINS
(C)netstat.exe
(D) DHCP
13.You verified that you have a network adapter installed and an appropriate client, but you cannot connect to computer B across NetBEUI. What could be the problem?
(A) You have the wrong IP address assigned to the computer.
(B) Computer B is not running NetBEUI.
(C) You should check the frame type on your computer.
(D) You need to install File and Printer Sharing to connect to another computer.
14.When you use ipconfig.exe, you do not see the IP address of the DHCP server that has given you the IP address. What should you do?
(A) Use ipconfig /renew at the command prompt.
(B) Use ipconfig /all at the command prompt.
(C) Ping the IP address of the DHCP server.
(D) Use ipconfig /release at the command prompt.
15.You installed a printer and want to share it out to the network. How can you do this?
(A) Use net print at the command prompt.
(B) Install the Client for Microsoft Networks.
(C) Configure the DHCP server on the network.
(D) Right-click the printer in the Printers folder and choose the Sharing command.
16.Which service is responsible for convertingwww.wiley.comto an IP address?
(A) DHCP
(B) DNS
(C) WINS
(D) ARP
17.You want to share the data folder as a resource to be used only by network administrators. How should you do this?
(A) Hide the share by naming it data$ and then set up the permissions so that only administrators have access. Tell the administrators the UNC path.
(B) Don’t share the folder; tell the administrators to go to the local computer to access the resource.
(C) Set up the share permissions so that only administrators have access to the share.
(D) Share the resource and don’t set any permissions.
18.You are installing a small network with six Windows 8.1 computers that will share resources between one another. You want to use a Class B address when configuring the IP address on the first system; which address would you use?
(A) 129.14.54.10
(B) 127.0.0.1
(C) 192.168.1.43
(D) 24.54.84.57
19.You are troubleshooting why Bob’s computer does not have Internet access so you use the ipconfig utility to view his TCP/IP settings. You notice his IP address is 169.254.34.56. Why can’t Bob access the Internet?
(A) There is a problem with the DNS server.
(B) There is a problem with the router.
(C) There is a problem with the DHCP server.
(D) There is a problem with the firewall.
Answers
D. To connect to a resource, you must have the appropriate client running. In this example, you are logging into a Windows server, so you must load the Client for Microsoft Networks. See “Network client.”
A. To connect to a shared resource on the network use the UNC path. The proper syntax for a UNC path is \\servername\sharename. Review “Using a UNC path.”
D.216.83.24.56 is an example of a Class C address, whose default subnet mask is 255.255.255.0. The other addresses are Class A and Class B, which have different default subnet masks. Check out “Subnet mask versus CIDR.”
A. The number in Class B addresses’ first octet ranges from 128 to 191. The number in Class A addresses’ first octet ranges from 1 to 126, and the number in Class C IP addresses’ first octet ranges from 192 to 223. Peek at “IP address.”
A, D. Because the computer is functioning on a small LAN with no router, all you need to configure the functionality of TCP/IP is the IP address and subnet mask. Because no information leaves the network, you do not have to configure a default gateway. Look over “The TCP/IP Protocol.”
B. The computer name, server1, must be converted to an IP address. WINS is the service that maintains a database that holds computer names and matching IP addresses. Study “WINS.”
B.tracert.exe is the utility used to see the number of networks between you and the remote host. ipconfig.exe and winipcfg.exe display the TCP/IP configuration. Refer to “TRACERT/traceroute.”
A, C, D. To participate on the Internet, you need an IP address, a subnet mask, and a default gateway. The default gateway is the IP address of the router that sends information off the network. Examine “Configuring TCP/IP in Windows.”
C. Address Resolution Protocol (ARP) converts the IP address to the network card address (MAC address). DNS and WINS convert different types of names to an IP address. See “ARP.”
B.ipconfig.exe is the utility run on Windows products to view TCP/IP configuration. winipcfg.exe is the utility on Windows 95 and Windows 98. Review “IPCONFIG/ifconfig.”
D. Dynamic Host Configuration Protocol (DHCP) is a service on a server that automatically assigns IP address information to each computer on the network, saving the network administrator from having to manually configure each computer. Check out “DHCP Server service.”
B. If you have a client and a network adapter installed, and they are working correctly, the reason why you cannot connect across NetBEUI is because the person on the other end is using a different protocol. Peruse “NetBEUI.”
B. Without switches, ipconfig.exe displays only the IP address, subnet mask, and default gateway. Use the ipconfig /all switch to view all TCP/IP configurations, including the DHCP server that assigned your computer an IP address. Take a look at “IPCONFIG/ifconfig.”
D. After you install File and Printer Sharing, you need to right-click the printer and choose the Sharing command. Peek at “Sharing Printer Resources.”
B. DNS is responsible for converting fully qualified domain names to IP addresses. WINS converts the computer name to an IP address, DHCP is responsible for automatic configuration of TCP/IP, and ARP is responsible for converting IP addresses to MAC addresses. Look over “DNS.”
A. The best way to be sure that no one except network administrators can access a shared resource is to share the resource and set the proper permissions. When you share the resource, though, it may be best to hide it from the network by making it a hidden share so that no one tries to sneak into it. Study “Sharing File System Resources.”
A. Answer is A because Class B addresses have a first octet that ranges between 128 and 191. Class A addresses have a first octet that ranges between 1 and 127, and Class C addresses have a first octet that ranges between 192 and 223. Refer to “IP address.”
C. Bob’s computer is using an APIPA address which is automatically assigned to the system when there is a problem contacting a DHCP server on the network. Examine “Special addresses.”
When building your network, it is important to identify the four major software components that allow a Windows OS to function in a networking environment:
I discuss each component in detail in the sections that follow. Be sure you are comfortable with them for the A+ Exams!
A USB network adapter is a popular choice today. If you go with a USB network adapter, you won’t need to open the computer — simply plug the USB adapter into an available USB port.
The network ID is not always the first two octets of the IP address. So how do you know which octets make up the network ID and which octets make up the host ID portion of the IP address? The class of IP address you have dictates which numbers correspond to which IDs. The three major classes of IP addresses are Class A, Class B, and Class C. The different IP address classes support a different total number of workstations on the network. For example, a Class A network (a network using Class A addresses) supports as many as to 16,777,214 network devices, a Class B network supports 65,534 network devices, and a Class C network supports only 254 network devices.
In the Number of Hosts column, two numbers are missing. For example, a Class C address could have 256 possible addresses, numbered 0 through 255. However, you are not allowed to use 0 because it is reserved for the network ID. Also, you are not allowed to use the 255 because it is the broadcast address, which is how systems send data to every computer on the network. To summarize, with each address class, you lose two addresses because of the network ID and the broadcast address.
Lab 3-1 gives you practice working with the 
(A) IP address