Testing Your Computer Network

By Doug Lowe from Networking For Dummies, 10th Edition

You've set up all your network switches, plugged in all the cables, and configured all your computers. One task remains before you can declare your network finished: You must verify that the network works as expected.

Here are a few simple tests you can conduct to make sure your network is functional.

Check the physical connections.

Check that the Link light — the little red or green light next to the RJ-45 port — is lit on every computer. You must check this light both on the computer itself and on the switch or router the computer is plugged into. If this light is not on, you have a connection problem — most likely a bad cable.
Verify that you can log on.

When you're sure the physical connections are good, you should attempt to log on to each of your network computers using a valid domain user account.
Check the network configuration.

Click the Start button, type cmd and press Enter. Then, enter the command ipconfig /all and press Enter.
This command will spit out numerous lines of information. The line you're looking for should resemble this:
```
   IPv4 Address. . . . . . . . . . . : 192.168.1.125(Preferred)
```
If this part of the output does not show a valid IP address, you need to check that your IP configuration is set correctly and that your DHCP server is working.
Verify that the computers can ping each other.

Another basic test you should perform is to use the ping command from a command prompt to make sure that the computers on your network can contact one another.

Do several ping tests. First, make sure that TCP/IP is up and running by having the computer try to ping itself. Open a command prompt and type ping localhost. The output from this command will indicate whether or not the ping was successful.

Next, try to ping your servers by name. For example, if your file server is named FileServer01, use the command ping FileServer01.