Go to a second computer; we will call this computer2.

82 | Lesson 4 6. Disable any secondary network adapters. Make sure only one adapter is enabled; this is the one you will use for the exercise.

7. Access the IP Properties window of computer2 and change the IP settings to reflect

the supplied subnet information. This time select 192.168.50.114. Again, no gateway address or subnet mask is necessary.

8. Click OK for both windows.

9. Return to computer1 and open the command prompt.

10. Type ipconfigall and verify that your settings are as they should be.

11. Now type ping 192.168.50.114. You should get replies If not, recheck your configu-

ration on both computers.

12. Now try pinging a host that is not within your network, such as 192.168.1.1. Type

ping 192.168.1.1. It should not reply, and you should get either a transmit failed error or a message similar to “Destination host unreachable,” depending on the OS used. Either way, the connection will fail because it is on a different network number. Even if a device does exist on that network number, it will not reply to you.

13. Now try pinging a host that is not within your subnet, such as 192.168.50.17. Type

ping 192.168.50.17. It should not reply, and you should get a similar error message as in step 12. This is shown in Figure 4-9. This ping attempt failed because the host is on a different subnet and, by default, cannot communicate with computers on your subnet. Figure 4-9 Failed ping from a computer on a subnet You now have a working subnet that compartmentalizes the two computers from the other subnets on the network. Network engineers create subnets to compartmentalize networks. This could be to decrease broadcasts, increase data throughput, add security, limit access, and use IP addresses more wisely. There are many other examples of subnetting, and there are other kinds of subnet masks you can use beyond subnet mask 255.255.255.240. For example, 255.255.255.224 gives you the ability to have eight subnets recommended six usable and thirty usable IP addresses per subnet. You can also create subnets within Class A networks and Class B networks as well. Tables 4-6 through 4-8 show all of the possibilities when it comes to subnetting within any of the three IP classes. These tables take into account the fact that most OS and IOS internetwork operating system manufacturers will recommend not using the first or last subnet for any given subnetting scheme. Understanding Internet Protocol | 83 Table 4-6 Class A subnetting matrix N ET ID S UBNET ID H OST ID M ASK OF U SABLE S UBNETS OF H OSTS PER 8 0 24 255.0.0.0 8 NA 16,777,14 8 1 23 255.128.0.0 9 NA NA 8 2 22 255.192.0.0 10 2 4,194,302 8 3 21 255.224.0.0 11 6 2,097,150 8 4 20 255.240.0.0 12 14 1,048,574 8 5 19 255.248.0.0 13 30 524,286 8 6 18 255.252.0.0 14 62 262,142 8 7 17 255.254.0.0 15 126 131,070 8 8 16 255.255.0.0 16 254 65,534 8 9 15 255.255.128.0 17 510 32,766 8 10 14 255.255.192.0 18 1,022 16,382 8 11 13 255.255.224.0 19 2,046 8,190 8 12 12 255.255.240.0 20 4,094 4,094 8 13 11 255.255.248.0 21 8,190 2,046 8 14 10 255.255.252.0 22 16,382 1,022 8 15 9 255.255.254.0 23 32,766 510 8 16 8 255.255.255.0 24 65,534 254 8 17 7 255.255.255.128 25 131,070 126 8 18 6 255.255.255.192 26 262,142 62 8 19 5 255.255.255.224 27 524,286 30 8 20 4 255.255.255.240 28 1,048,574 14 8 21 3 255.255.255.248 29 2,097,150 6 8 22 2 255.255.255.252 30 4,194,302 2 8 23 1 255.255.255.254 31 NA NA 8 24 0 255.255.255.255 32 NA NA