Type the command route delete 192.168.1.0 mask 255.255.255.0. This should

118 | Lesson 5 d. Type the command route print to view the results. If you start to have any issues with your routing table, consider stopping and restarting TCPIP, or even restarting the computer. By the way, TCPIP can be reset in the command line by typing the following command: netsh int ip reset c:\resetlog.txt. Generally, these added routes will be lost if TCPIP or the computer is restarted. However, routes can also be added in a persistent manner by using the –p option. The p stands for persistent; it preserves the route within the registry even if TCPIP is restarted. Again, the idea behind routing is to make connections to remote networks. See Figure 5-24 for some network documentation. Figure 5-24 Routing documentation Cloud Router A Router B Switch A Switch B LAN A LAN B E 10.254.254.1 E 10.253.253.1 S 63.21.15.121 S 63.21.15.128 In the figure, there are two LANs, LAN A and LAN B. By default, computers on these LANs would not be able to talk to each other because they are separated by routers and the “cloud” whatever “the cloud” happens to be. To allow the computers on each LAN to talk to each other, a specific route would have to be created on each LAN’s router. Each router has a LAN address known as E and a WAN address known as S . These are also known as private and public addresses, respectively. Let’s say that the subnet mask used on both LANs is 255.255.255.0, just like the CIDR setup we have been using. On router A, we would need the following syntax: Route add 10.253.253.0 mask 255.255.255.0 63.21.15.121 This makes the connection to the 10.253.253.0 network utilizing the LAN B router’s public address. This address is labeled as S , or the first serial connection, which is used to connect to different networks. On router B, we would need the following syntax: Route add 10.254.254.0 mask 255.255.255.0 63.21.15.128 This makes the connection to the 10.254.254.0 network utilizing the LAN A router’s public address. Once these two connections have been made, communications should be possible between the two LANs. If the routers are Windows Servers, some additional configuration would be necessary prior to adding these route line items. The servers would need to be equipped with two network adapters, making them multi-homed computers. Then, Routing and Remote Access would have to be configured to allow for IP forwarding. Alternate software such as ISA could also be used. After that, the route line items could be added. If you were using conventional black box routers or appliances, TCPIP protocols such as RIP and OSPF would be employed to streamline and automate the process: • Routing information protocol RIP is a distance vector protocol that uses algorithms to decipher which route to send data packets. Implementing TCPIP in the Command Line | 119 • Open shortest path first OSPF is a link-state protocol that monitors the network for routers that have a change in their link-state, meaning whether they were turned off or on or restarted. We’ll talk more about routing protocols in Lesson 7. UTILIZE THE NET COMMAND GET READY. Although not really considered part of the TCPIP command set, the net com- mand can display all kinds of important networking data, and it allows you to configure various networking options such as services.

1. Type the net command. View the results. You will see options such as view, user, ses-

sion, start, and stop. Each of these options can help you analyze networking configu- rations and make modifications.

2. Type the command net view. This should show the computers on your immediate net-

work, whether they operate as a workgroup or a domain. Each computer listed is pre- ceded by a double backslash. This indicates a UNC or Universal Naming Convention. The UNC can be used when mapping drives and connecting to computers for other reasons. 3. Type the command net time \\[localcomputer]. For example, type net time \\ desktop-lamp1, as shown in Figure 5-25. This displays the current time of the computer. This command can also be used to synchronize time to other computers or time servers. Figure 5-25 Net time

4. Type the command net user to display the user accounts on the computer.

5. Type the command net stop themes. This will stop the themes service that controls

your desktop themes.

6. Type the command net start themes to restart the service.

This only scratches the surface of what the net command can do. This command can be incredibly useful to network administrators. Examine some of the other options by typing net followed by the option and then ? e.g., net time ?. Table 5-1 reviews the TCPIP commands we covered in this lesson. Table 5-1 Summary of TCPIP commands C OMMAND D ESCRIPTION Ipconfig Displays information pertaining to your network adapter, namely TCPIP configurations. Ping Used to test the existence of other hosts on the network. Netstat Used to display active TCP or UDP connections. Nbtstat Displays NetBIOS over TCPIP statistics for local and remote computers. Tracert Shows paths to a destination on another network. It does this by pinging each step along the way three times. continued 120 | Lesson 5 S K I L L S U M M A R Y I N THIS LESSON , YOU LEARNED HOW TO : • Work with the command prompt as an administrator and in an efficient manner. • Use basic TCPIP commands such as ipconfig and ping to analyze and test a network. • Use more advanced commands such as netstat, nbtstat, tracert, pathping, route, and netsh to fully examine a computer and configure it in the command line. • Work with the Net command in an effort to find out more information about a system, start and stop services, and work with the network configuration. Table 5-1 continued C OMMAND D ESCRIPTION Pathping Similar to tracert, but also computes the degree of packet loss. NSLookup Displays information about DNS names and their corresponding IP addresses and can be used to diagnose DNS servers. FTP Is an application layer protocol as well as an application. The FTP command is used in the command prompt to connect to FTP servers. Telnet Used to take control of a remote computer via the command line. Netsh A built-in command-line scripting utility that allows you to display and modify network configurations of the local computer. Route Lets you display and make changes to the local IP routing table of the computer. Multiple Choice Circle the letter that corresponds to the best answer.

1. You are troubleshooting a network connectivity problem and see the command results

listed here. What command was typed to acquire these results? Request timed out. Request timed out. Request timed out. Request timed out. Packets: Sent = 4, Received = 0, Lost = 4 100 loss,

a. ipconfig b. netstat

c. ping d. nbtstat

2. You are told to determine the MAC address of a Windows computer. Which command

should you use to find this information? a. ipconfig

b. ipconfig all

■ Knowledge Assessment