Type the command ping 127.0.0.1. Type the command ping [IP address]. For example ping 10.254.254.252.

106 | Lesson 5 other hosts on the same network, ultimately ending up with the router. Next, try pinging hosts on other networks.

9. Ping a computer with a larger packet size:

a. Select another computer to ping; it could be a partner’s computer, a secondary

computer, or a router. Make note of its IP address. For this example, we will use the address 10.254.254.1. b. Type the command ping –1 1500 [IP address]. For example, ping –1 1500 10.254.254.1. The results should be similar to Figure 5-9. Notice that each of the replies equals 1,500 bytes instead of the standard 32 bytes. The –1 option allows you to modify the packet size of the ICMP echoes that are sent. The most bytes that you can send in this fashion is 65,500; however, this will create fragmented packets. This ping option can help simulate network traffic to a particular host. Figure 5-9 Ping –l

10. Ping a computer X amount of times:

a. Use the same computer you pinged in step 9.

b. Type the command ping –n 10 [IP address]. For example, ping –n 10 10.254.254.1. The results should be similar to Figure 5-10. Notice that there were a total of 10 ICMP echo replies. The –n option allows you to ping with as many ICMP packets as you wish. This particular option works well if you are creating a performance baseline. By running a command such as ping –n 1000 10.254.254.1 every day, you could compare the results to see whether the destination computer is performing better or worse than usual. Figure 5-10 Ping –n Implementing TCPIP in the Command Line | 107 11. Ping a computer continuously:

a. Use the same computer you pinged in steps 9 and 10.

b. Type the command ping –t [IP address]. For example, ping –t 10.254.254.1. This command option sends pings endlessly to a destination IP address. This can only be stopped by pressing Ctrl + C on the keyboard or by closing the command prompt altogether. This option works well if you need to test whether a network connection is being made. For example, if you aren’t sure which patch cable to use or which RJ45 port to connect to, you could run this command, then test one connection at a time, checking the results on the screen each time until you get replies. By the way, most of the time, an option can be typed after an IP address as well. However, it is a good habit to place options directly after the command they are modifying. These are just a few of the ping options, but they are some of the more commonly used ones. Do your best to memorize the various switches we employed during this exercise. ■ Working with Advanced TCPIP Commands Advanced TCPIP commands like netstat, nbtstat, and tracert allow you to analyze more facets of a TCPIP connection than ipconfig and ping can. Also, FTP, Telnet, netsh, and route allow you to do more than just analyze a system—they can help you configure the system. THE BOTTOM LINE In the following exercises, we will be showing results from two computers. One is a server computer; its command prompt windows will be displayed with a black background. The other is a client computer; its command prompt windows will be displayed with a white background. The results work basically the same way on both types of computers; however, a server computer will often have more results because it generally has more networking connections. ANALYZE THE TCPIP CONFIGURATION WITH NETSTAT AND NBTSTAT GET READY. In this exercise, we will analyze our system with the netstat and nbtstat commands. Both show statistics of the network connection, but netstat centers on the local computer, whereas nbtstat can also show statistics for remote machines:

1. Type the command netstat and view the results. They may take up to a minute to

appear, depending on your network configuration and number of current network connections. Your results should be similar to Figure 5-11, although you may have fewer line items of information. The netstat command is used to display active TCP or UDP connections, as well as a host of other statistics that we will cover later in the exercise. Note that there are four columns. The Proto column shows the transport layer protocol being used for the connection. The netstat command by itself only shows TCP connections in this column. The Local Address column displays the local computer by name server2003, followed by the outbound port number. The Foreign Address column shows the remote computer that is being connected to; in some cases, this can be the same computer. The State column shows what the status of the connection is for example, CERTIFICATION READY How do you configure TCPIP commands with TCPIP? 3.6