Networking
Internet Connection Sharing: Don't bother. All
versions of Windows released since Windows
98 SE include a feature called Internet
Connection Sharing (ICS) that lets you share a
dial-up, cable, or DSL Internet connection with
multiple PCs. Though it sounds good on paper,
ICS can be difficult to configure and manage.
First of all, ICS requires that you designate one
computer as the gateway PC through which all
your Internet traffic passes, and this PC must be
powered on for the other computers to connect
to the Internet. Second, unless you're sharing a
dial-up connection, you'll need to install two
network cards in the gateway: one that connects
to the broadband modem and one that connects
to your LAN.
In most cases, you'll be far better off with an
Internet gateway router, such as those sold by
D-Link and Linksys. These devices provide a
connection between your LAN and the Internet.
They're inexpensive (they're available for as little
as $49) and easy to install, and they use very
little power. Virtually all gateway routers use
Network Address Translation, or NAT, to share
your DSL or cable modem's single IP address
with all the PCs on the LAN. Better still, most
routers include a firewall feature that helps
protect your LAN from hackers and intruders.
Don't have a broadband connection? In some
cases a gateway device includes a serial port or
an internal modem so that you can use it to share
a dial-up or ISDN connection. Some models
include 802.11 wireless network access points;
others have built-in print servers; and almost all
include three- or four-port 10/100 Ethernet
switches.
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Fix A Mangled IP Configuration. In
the days before Windows XP, a corrupted IP
installation could often be fixed simply by
removing and reinstalling TCP/IP. In most cases,
the IP-related files remained intact, but some
related Registry keys would be corrupted
beyond repair.
You can't uninstall TCP/IP in Windows XP,
because there is no Uninstall button for this
protocol. According to Microsoft, that is
because TCP/IP is an integral part of the
operating system, and removing it would cause
major problems. You can, however, use the
Windows XP command line utility NetShell to
reset all IP-related Registry settings to their
default values. The result is a brand-new TCP/IP
configuration.
The Netsh.exe program is located in the
C:\Windows\System32 directory. To use the
program, enter the command "netsh int ip reset
filename." You must specify a filename, such as
Ipstuff.txt. After Netsh .exe runs, the file will
contain a detailed log of the Registry keys that
were modified.
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Use The Alternate IP Configuration Feature. If
you routinely move your laptop between two
locations, you should know about Windows
XP's alternate IP configuration feature. If one
location (your office, for example) requires a
fixed IP address configuration, you can specify
the office IP address, gateway address, and
DNS server address information in the Alternate
Configuration tab of the TCP/IP Properties page.
When your computer starts, it automatically
attempts to obtain an address from a DHCP
server. If no DHCP server is found, Windows
uses the alternate IP address information. If a
DHCP server is found (as would happen on a
home LAN with an Internet gateway device), the
system uses the DHCP-provided address
instead.
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Use Network Bridging. Windows
XP has a new feature called Network
Bridge, which lets you connect disparate media
types into one seamless LAN. For example, if
you have a network PC connected to a LAN,
cable modem, or DSL modem via Ethernet, you
can create a bridge between the Ethernet
connection and your PC's FireWire connection.
When you connect a laptop to the desktop via
FireWire, the Network Bridge provides an IP
connection to the laptop, even though the laptop
isn't connected directly into the network. To
create a bridge, select two connections in the
Network Connections control panel, then
right-click on them and select Bridge
Connections.
If you are bridging an Ethernet connection to a
FireWire connection, you must manually set the
IP address information (including IP address,
gateway address, and DNS server address) on
the FireWire-connected laptop, even if the LAN
is configured to assign IP addresses automatically
using a DHCP server. If you frequently connect
the same laptop to the same desktop, you can
use the alternate IP address configuration feature
to set the IP address to use for the FireWire
connection.
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Install NetBEUI For Compatibility With Older LANs. Previous
versions of Windows automatically
installed Microsoft's NetBEUI protocol
whenever you installed a LAN card. Windows
XP, however, doesn't do this. If you want to
share files and printers with older Windows
systems that don't have IP installed, you'll need
to install NetBEUI manually.
Although NetBEUI is not officially supported, the
files needed to install it are on the Windows XP
CD. To install NetBEUI:
• Browse to the Valueadd\MSFT\Net\NetBEUI
folder on your Windows XP CD.
• Copy Nbf.sys to the C:\Windows\System32\Drivers directory.
• Copy Netnbf.inf to the Windows\Inf directory.
Once you've copied these files to the proper
directories, you can add NetBEUI to most
network connections using the Install... button on
each connection's Network Connection
Properties display. Unfortunately, you can't install
NetBEUI on a FireWire connection.
NetBEUI doesn't require any addressing,
routing, or other configuration information, so it is
very handy for file sharing between laptops. If
you have NetBEUI installed on two computers,
you can simply connect them together (using an
Ethernet hub or crossover cable) to share files
and printers.
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Automatic Wireless Device Configuration. Windows
XP includes built-in drivers for several
popular wireless LAN cards. In most cases, you
can simply pop in a wireless card and use it with
no configuration changes. But the generic
Microsoft wireless LAN driver doesn't provide
access to some manufacturer-specific features,
like manual channel selection and proprietary
authentication schemes.
If you need access to these features, you'll need
to install the driver provided with your wireless
card. But be aware that if you install a
manufacturer-specific driver, you may lose the
ability to connect to any wireless LAN you may
encounter. Whereas Windows XP automatically
connects to any new wireless LAN that it sees,
some manufacturers' drivers don't let you do this
without changing settings (usually the
system-specific ID, or SSID) in the LAN card
driver.
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Networking with FireWire. Although
FireWire was originally designed to
connect high-speed peripherals such as hard
drives and CD-ROM drives, it can also be used
as a very fast (400-Mbps) way to network two
PCs. In fact, Windows XP automatically creates
a network connection for FireWire adapters. The
connection appears in the Network Connections
control panel as 1394 Connection, and it works
much like any Ethernet connection.
Unlike USB (which requires a special crossover
cable to connect two PCs together), a FireWire
connection requires no special cables, hubs, or
adapters. Be aware that there are two types of
FireWire connectors in common use. The larger,
six-pin connector is most often used for external
hard drives, CD drives, and other AC-powered
equipment, while the smaller four-pin connector
is used on DV camcorders and small, portable
equipment. Be sure to get a cable with the
appropriate connections.
Use the Hosts, Luke! Whenever
your computer connects to a resource
on the Internet, it uses a Domain Name System
(DNS) server to convert the human-friendly host
name (such as \\Mailserver) or URL (such as
www.pcmag.com) into an IP address. A
little-known feature (lifted directly from Unix) in
Windows 98 SE or later lets you keep a table of
host names and IP addresses on your own
computer. If this file - called the Hosts file - is
present, Windows uses the IP address from the
file without consulting a DNS server.
The Windows Hosts file can be found in
C:\Windows\System32\Drivers\. (In Windows
98 SE, the Hosts file is located in \Windows\.) The
plain-text Hosts file contains one line for
each entry.
Even if you haven't created the Hosts file, it's
there - with one lonely entry that defines
localhost. (Localhost is an alias used for testing,
and it always refers to 127.0.0.1, the IP standard
loopback address.)
You can add your own entries to the Hosts file
using any text editor, such as Notepad. The first
(and less useful) way you might use this is to add
the names and IP addresses of commonly used
Internet hosts, so that Windows does not have to
look up the address each time it connects to a
given host. But most DNS lookups are so fast
that you won't notice any performance increase.
The second, more useful way to use Hosts is to
create a dead-end address, known as a hacker
IP address, for ad servers or for Web sites that
you want to block. For example, the entry
127.0.0.1 adserver.annoying.com tells Windows
to use 127.0.0.1 to connect to
Adserver.annoying.com. Since that address
doesn't exist, you'll never see the ad. You can
use the Hosts file as a cheap and dirty content
filter in the same way: Simply create an entry for
each host you want to block, using the address
127.0.0.1.
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Where'd that printer come from? The
Automatic Search for Network Printers and
Folders may have been intended to make your
life a little simpler. But this time-saving feature
can be a real annoyance if you work on a large
LAN or move your laptop among several
networks.
When your computer is connected to a LAN,
this feature periodically polls the network to see
whether any new printers or shared directories
are available on the LAN. When Windows XP
detects a new shared directory, it automatically
adds a shortcut icon to My Network Places. Similarly,
new printers are added to the Printers
and Faxes folder. This can be convenient on a
small LAN with just a few shared folders and
printers, but on larger LANs, where users don't
want or need to see every shared resource, this
feature can cause confusion.
Fortunately, the auto-search feature is easy to
turn off. Go to the Control Panel and open
Folder Options. Then click the View tab. The
first item in the Advanced settings area is
Automatically search for network folders and
printers. Uncheck the check box to turn the
feature off.
Find your IP address. To
get basic information about your TCP/IP
network connection, you can use the Winipcfg
utility in Windows 98 and Me (Start | Run |
winipcfg), or use Ipconfig/all from a command
prompt if you're running Windows 2000 or XP.
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Snoop on snoopers. Turnabout
is fair play. The built-in networking
features in Windows XP make it easy for other
users to connect to your PC to use shared files
and printers. Unfortunately, those features also
make it easy for snoopers, hackers, and
backdoor programs to compromise your
system's security.
Your first line of defense should be a
combination of a secure firewall and a good
antivirus program. But even with these security
measures in place, Trojan horse programs,
e-mail viruses, and other nasty code can still get
past your defenses.
If you suspect that someone (or something) is
accessing your PC over a network or the
Internet, there's an easy way to tell. The
command line utility Netstat shows the status and
address of every connection to your PC. Open a
command line window and type Netstat -a to
see a complete list of all the open connections to
and from your PC.
Don't panic if you see lots of connections; most
of them are supposed to be there. If you see a
suspect item in the connections list, you can type
Netstat -o to get the Windows process ID
number for each connection. You can then match
up the process ID number with the list of running
tasks from Task Manager to see which programs
are using which connection.
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Net Diagnostics, Hidden
in Windows XP's System Information
utility is a very good tool for getting a lot more
information about what's going on. Go to Start |
All Programs | Accessories | System Tools |
System Information. Then choose Net
Diagnostics from the Tools menu. The program
will ping your DNS servers, gateways, SMTP
and POP3 mail servers, and proxies; test your
modem and network adapters; and supply very
detailed reports about your settings, as well as
which tests passed and which failed.
Copyright (c) 2002 Ziff Davis Media Inc. All Rights Reserved.