In This Chapter
Checking the network configuration settings Pinging yourself and others
Making sure that you can log on
Verifying mapped drives and checking network printers
You’ve installed all the network cards, plugged in all the cables, and configured all the software. However, one task remains before you can declare your network finished: You must verify that the network works as expected.
Verifying a network is not difficult. All you have to do is make sure that users can log on and access the network resources they need. If everything works the way it should, you can declare victory, give yourself a high five, and take the afternoon off. If not, you have to do some troubleshooting to determine the source of the problem.
In this short chapter, I describe some of the tests that you should perform to make sure that your network is functioning. Along the way, I suggest a few of the most common problems that may interrupt the network. However, the focus of this chapter is on verifying that your network is functioning — not on troubleshooting it if it isn’t. For information about network troubleshooting, refer to Book IV.
Incidentally, most of the techniques described in this chapter work from an MS-DOS command prompt. You can open a command prompt by choosing Start➪Run, typing Commandas the name of the program to run, and then clicking OK.
Is the Computer Connected to the Network?
This one is easy to check. Just check the Link light on the computer’s net- work interface card and the light on the network hub or switch port that the computer is connected to. If both are lit, the computer is connected to the network. If one or both are not lit, you have a connection problem. Several things may be wrong:
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✦ The patch cable that connects the computer to the wall outlet or that connects to the hub or switch may be bad. Replace it with one that you know is good in order to verify this problem.
✦ The cable run between the wall outlet and the patch panel may be bad.
The cable may be physically broken, or it may be routed right next to a 20,000-watt generator or an elevator motor.
✦ The computer’s NIC may be bad or configured incorrectly. Check the configuration settings. If necessary, replace the card.
✦ The hub or switch may be bad.
Is the Network Configuration Working?
You can run three commands from a command window to verify the basic con- figuration of each computer. These commands are Net Config Workstation, Net Config Server, and Ipconfig.
The Net Config Workstationcommand displays basic information about the computer’s network configuration. Here’s a sample of the output it displays:
C:>net config workstation
Computer name \\DOUG Full Computer name doug User name Doug Lowe Workstation active on
NetbiosSmb (000000000000)
NetBT_Tcpip_{FC6D2F39-FDDD-448E-9B3C-0C12847F2B61}
(0050BA843911)
Software version Windows 2002 Workstation domain WORKGROUP Workstation Domain DNS Name (null) Logon domain DOUG COM Open Timeout (sec) 0 COM Send Count (byte) 16 COM Send Timeout (msec) 250 The command completed successfully.
The most important information to check in the Net Config Workstation command’s output is the computer name and domain information.
If the computer is configured to enable File and Print Sharing, you can also run Net Config Serverto display basic information about the server con- figuration. Here’s a sample of its output:
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C:>net config server
Server Name \\DOUG Server Comment
Software version Windows 2002 Server is active on
NetbiosSmb (000000000000)
NetBT_Tcpip_{FB6D2F79-FDDF-418E-9B7C-0C82887F2A61}
(0050ba843911)
Server hidden No Maximum Logged On Users 5 Maximum open files per session 16384 Idle session time (min) 15 The command completed successfully.
The Ipconfigcommand displays information about the computer’s TCP/IP configuration. If you type ipconfigby itself, the computer’s IP address, subnet mask, and default gateway are displayed. If you type ipconfig /all, you see more detailed information. Here’s typical output from the Ipconfig /All command:
C:>ipconfig /all
Windows IP Configuration
Host Name . . . : doug Primary Dns Suffix . . . :
Node Type . . . : Unknown IP Routing Enabled. . . : No WINS Proxy Enabled. . . : No Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : we1.client2.attbi.com
Description . . . : D-Link DFE-530TX+
PCI Adapter
Physical Address. . . : 00-50-BA-84-39-11 Dhcp Enabled. . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . : 192.168.1.100 Subnet Mask . . . : 255.255.255.0 Default Gateway . . . : 192.168.1.1 DHCP Server . . . : 192.168.1.1 DNS Servers . . . : 204.127.198.19
63.240.76.19 Lease Obtained. . . : Saturday, May 24, 2003 6:28:49 PM
Lease Expires . . . : Sunday, May 25, 2003 6:28:49 PM
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The most important information to glean from this output is the computer’s IP address. You should also verify that the default gateway matches the IP address of your Internet router, and that the IP addresses for the DHCP and DNS servers are correct.
Can the Computers Ping Each Other?
A basic test that you can perform to ensure that your network is functioning is to use the Pingcommand from a command prompt to make sure that the computers on the network can contact each other. The Pingcommand simply sends a packet to another computer and requests that the second computer send a packet back in reply. If the reply packet is received, Ping displays a message indicating how long it took to hear from the other com- puter. If the reply packet is not received, Pingdisplays an error message indicating that the computer could not be reached.
You should try several Pingtests. First, you can make sure that TCP/IP is up and running by having the computer try to pingitself. Open a command prompt and type ping 127.0.0.1(127.0.0.1 is the standard loop-back address that a computer can use to refer to itself). If you prefer, you can also type ping localhost.
Next, have the computer pingitself by using the IP address displayed by the\Ipconfigcommand. For example, if Ipconfigsays the computer’s IP address is 192.168.0.100, type ping 192.168.0.100at the command prompt.
Now try to pingyour servers. You’ll have to run Ipconfigat each of the servers to determine their IP addresses. Or, you can just ping the computer’s name.
A final test is to make sure that you can pingthe workstation from other computers on the network. You don’t have to try to pingevery computer from every other computer on the network unless you’ve determined that you have a connectivity problem that you need to pinpoint. However, you should try to pingeach workstation from each of the servers, just to make sure the servers can see the workstations. Make a list of the IP addresses of the workstations as you test them and then take that list to the servers and pingeach IP address on the list.
Can You Log On?
After you’ve established that the basic network connections are working, the next step is to verify that network login works. This is as simple as attempt- ing to log in from each computer by using the correct user account for the computer. If you can’t log in, several things may be causing the problem.
Here are the most common:
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✦ You may not have the right user account information. Double-check the user name, password, and domain.
✦ Make sure that the domain name is correct.
✦ Passwords are case-sensitive. Make sure that you type the password cor- rectly and that the Caps Lock key is not on.
✦ You may not have a computer account for the computer. Double-check the computer name and make sure that you have a valid computer account on the server.
✦ Double-check the user account policies to make sure that there isn’t something that would prevent the user from logging in, such as a time of day restriction.
Are Network Drives Mapped Correctly?
After you know the user can log on, you should make sure that mapped net- work drives are available. To do so, type net useat a command prompt.
You’ll see a list of all the network mappings. For example:
C:>net use
New connections will be remembered.
Status Local Remote Network
--- OK M: \\Doug\Prod Microsoft Windows Network OK X: \\Doug\admin Microsoft Windows Network OK Z: \\Doug\Marketing Microsoft Windows Network The command completed successfully.
Here, you can see that three drives are mapped, and you can tell the server and share name for each mapped drive.
Next, try to display a directory list of each drive to make sure that you can actually reach it. For example, type dir m:. If everything is working, you see a directory of the shared folder you’ve mapped to drive M:.
Do Network Printers Work?
The final test I describe in this chapter is making sure that your network printers work. The easiest way to do this is to print a short document to the network printer and make sure that the document prints. I suggest that you open Notepad (Start➪Accessories➪NotePad), type a few words (like “Yo, Adrianne!”), and then choose File➪Print to bring up the Print dialog box. Select the network printer and click OK.
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If the network printer doesn’t appear in the list of available printers, go to the Printers and Faxes window and recheck the network printer. You may have incorrectly configured the printer. If the configuration looks okay, go to the printer itself and make sure that it is turned on and ready to print.
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Book III
Network
Administration and Security
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Contents at a Glance
Chapter 1: Help Wanted: Job Description for a Network Administrator ...159
Chapter 2: Security 101 ...173
Chapter 3: Managing User Accounts ...183
Chapter 4: Firewalls and Virus Protection ...191 16_599399_pt03.qxd 8/18/05 10:57 PM Page 158