10. Troubleshoot Network Connections
Whether
you're connected wirelessly or with a cable, Vista needs certain
details to be squared away, or nothing will work right. With that in
mind, you should get to know the Network Connections window shown in Figure 17.
In
versions of Windows before Vista, the Network Connections window was
the central interface for all network settings. With the introduction of
the Network and Sharing Center—from which you can open Network
Connections by clicking the Manage network connections
link—this is no longer entirely true. But it's still the best way to
fine-tune your TCP/IP settings and fix many networking problems. If you
haven't done so already, open the Views drop-down and select Details to show the pertinent information.
Here you'll see the status of all your network adapters—both wireless and wired—at a glance. The Status
column tells you which connections, if any, are connected, albeit with
some inconsistencies. Wireless and Bluetooth adapters that are not in
use say Not connected, but Ethernet (wired) adapters say Network cable unplugged. In either case, any adapter currently in use (connected) is marked only with Vista's current network name.
Don't let the network name throw you. It's not the SSID of the wireless network you're using , nor is it the workgroup name used for sharing folders and printers , nor does it have anything to do with your Internet connection. Rather, it's a name you can enter by clicking the Customize link in the Network and Sharing center, used to make it easy to switch between public and private networks. |
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Also important is the Connectivity column, which shows exactly what each adapter is providing (e.g., Access to Local and Internet).
But the main reason to use this window is to change TCP/IP settings. Right-click the connection you're using and select Properties. Then, select Internet Protocol Version 4 (TCP/IPv4) from the list and click the Properties button to open the Properties window shown in Figure 18.
In most cases, selecting the Obtain an IP address automatically and Obtain DNS server address automatically
options will suffice. This works because your router, if you have one,
automatically assigns a unique IP address to each new PC it sees using
Dynamic Host Configuration Protocol (DHCP).
But
sometimes DHCP doesn't cooperate as well as it should; either a PC is
given the wrong IP address or no address at all. Or, for a variety of
reasons (such as enabling remote control), you need a PC to always have the same IP address. To do this,
you need to pull your PC out of the DHCP arena and assign it a static (nonchanging) IP address:
If you have a router, open its configuration page in a web browser (usually http://192.168.1.1 or http://192.168.0.1),
and navigate to the DHCP client table. This shows all the PCs connected
to your network (both wired and wireless) controlled by DHCP, along
with their dynamically assigned IP addresses. (In most cases, PCs with
static addresses will be absent from this list.)
Open the Internet Protocol Version 4 (TCP/IPv4) Properties window as described at the beginning of this section, and select Use the following IP address.
For the IP address, type the address you want to use (e.g., 192.168.1.107).
Often,
networks don't work because Windows and your router are unable to
negotiate the correct addresses automatically. The first three numbers
in each PC's IP address (e.g., 192.168.1.xxx)
must exactly match the first three numbers in the IP address of your
router—usually 192.168.1.1 or 192.168.0.1—which you can get from your
router's documentation. The last number (e.g., 100, 101, 102) must be
different for each PC. |
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For the Subnet mask, type 255.255.255.0.
For the Default gateway, type the IP address of your router (usually 192.168.1.1 or 192.168.0.1).
For the Preferred DNS server and the Alternate DNS server, type the IP addresses of your ISP's primary and secondary DNS servers, respectively.
If
you don't know the DNS addresses, contact your ISP. If you're on a
public network or you're using a friend's ISP, open a web browser, type http://www.annoyances.org/ip in the address bar, and press Enter to show the true IP address of your Internet connection. Then, open a Command Prompt window and type nslookup
ip_address, where ip_address is the set of four numbers reported by Annoyances.org. This should give you the name of your ISP, plus some extra stuff. So, you might see something like dsl456.eastcoast.superisp.net, which means your ISP is superisp.net. Then, it's only a matter of visiting the ISP's web site (e.g., http://www.superisp.net/) and determining its DNS server addresses from its online documentation.
Click OK in both boxes when you're done.
These
static IP numbers, provided you've typed them correctly, will help
ensure that all the PCs on your network can communicate reliably with
one another. You don't have to set static IP addresses on all the PCs on
your network, but it may help settle a cranky network, particularly one
with computers running several different operating systems (Linux, Mac
OS X, older versions of Windows, etc.).
Return to the Network Connections window when you're done, and look at the Status column entry for the connection you've just modified. If it says Acquiring network address,
it means Windows is in the process of establishing a connection; if you
see this for more than, say, 10 seconds, you've probably done something
wrong. If the status is Limited or no connectivity, it means that a connection has been established, but your IP address is incorrect.
If,
at this point, your network appears to be functioning, you can proceed
to set up the various services you need, such as file and printer
sharing
and Internet Connection Sharing .
Otherwise, look through the following checklist for possible solutions:
Restart
Restarting your computer will fix 99% of all problems. This is never truer than when diagnosing a networking problem.
Bad cables?
Make
sure the green light is on next to each cable you've plugged in. If
not, try replacing one or more of the cables, especially if they're old
or their connectors are worn.
Blinkenlights
When
you transfer data across a network connection, each network card and
the hub (if you have one) should have an "activity" light that flashes.
Some devices have separate lights for receiving and transmitting data,
while others have only a single light for all incoming and outgoing
communication. Activity lights tend to flash intermittently and
irregularly; if they flash regularly, it could be a sign of a problem
with one of the devices.
No dupes
Make sure no two computers on your network are attempting to use the same IP address or computer name (set in Control Panel → System → Advanced system settings → Computer Name tab).
Drivers
Make
sure you have the latest drivers for each network adapter on your PC,
and remove any proprietary network software that may have come with your
network hardware.
Firmware
Nearly
all network hardware (adapters, routers, print servers, etc.) has
user-upgradable firmware. Check the manufacturer's web site for the
latest firmware if you're experiencing any network problems.
Device Manager
Some
problems are caused by improper hardware settings, usually attributed
to the network adapter itself. Open Device Manager and double-click the
icon for your troublesome adapter (or right-click it in the Network
Connections window, select Properties, and then click Configure). Choose the Advanced tab, and thumb through the Property
list on the left, looking for possible problems. If you don't
understand a particular setting, look it up in the documentation or on
Google.
Can't "see" another PC
This is a nasty problem, one with several different causes and often no clear-cut solution. First, open the Services window (services.msc), find the Computer Browser service, and make sure its Status is Started and its Startup Type is Automatic (if it isn't, double-click the service to change its settings). Next, try the Ping utility, described in "Section 7.1.11,"
to determine whether your PC can actually see another PC on your
network. If the Ping test fails, try pinging your router (if you have
one) from each computer to see which PC's connection isn't working.
10.1. Add new network connections
You
may have noticed that there's no obvious way to add a new connection to
the Network Connections window. By default, the Network Connections
window only shows your installed hardware, which means you can add a new
network adapter, and it will show up in this list.
But the Network Connections window also supports virtual
connections, such as dial-up (analog modem) connections and broadband
(PPPoE) connections. To add one of these, open the Network and Sharing
Center and click the Set up a connection or network link. Of course, you'll have to return to the Network
Connections window if you want to modify or delete one of these virtual
connections.
If you ever use more than one network connection at once, see the next sidebar, "Prioritize Network Connections," for a way to get the desired results.
There's
a little-known setting you can play with that may solve problems if you
have more than one network adapter on your PC. Say you connect
wirelessly at home most of the time, but when you transfer a lot of
files from one PC to another, you prefer to use a cable for greater
speed. Except in specific cases, Windows Vista will only use one network adapter at a time. So, if you're connected wirelessly and with a cable, you'll want to choose which connection Windows prioritizes. In the Network Connections window, press the Alt key to temporarily show the menu, and then from the Advanced menu, select Advanced Settings. Pick the fastest connection, and use the up arrow to move it to the top of the list. While you're here, choose the Provider Order tab, and make sure the Microsoft Windows Network entry appears at the top of the list. Click OK when you're done; the change will take effect immediately. |
11. Test an IP Address
One
surefire way to test a connection is to use the Ping utility, which
essentially sends small packets of information to another computer on
your network, and reports on its success (if any).
Open the Start menu, type cmd, and press Enter to open the Command Prompt. At the prompt, type ping
address, where address is the IP address of another computer or perhaps your router. For example, from the computer at 192.168.1.102, you'd type:
ping 192.168.1.101
If the connection is working, the Ping transaction will be successful, and you'll get a result that looks like this:
Pinging 192.168.0.1 with 32 bytes of data:
Reply from 192.168.0.1: bytes=32 time=24ms TTL=53
Reply from 192.168.0.1: bytes=32 time=16ms TTL=53
To be fair, this test only works if both connections are working, and if the network is functional. If you get this result:
Pinging 192.168.0.1 with 32 bytes of data:
Request timed out.
Request timed out.
it means that Ping never got
a response from the other computer. A failed Ping can mean that the
adapter on your local PC is misconfigured, or that the target machine
isn't up and running.
You can also test your Internet connection by pinging a host outside your local subnet, like this one:
ping 64.233.187.99
Now, if you get a reply from 64.233.187.99, but no reply when you ping a host name, like this:
ping google.com
it
means that your DNS nameservers—the machines at your ISP that translate
host names to their IP addresses and back—are misconfigured or possibly
down.
