Before your computers can share your Internet
connection, they need to be able to share with each other!
This means that you'll have to connect them together to form a LAN.
If you already have an Ethernet-based LAN, then you can go on
to the next
page. If you don't, or aren't sure, then read on.
What's a LAN? A LAN, or Local
Area Network is a group of two or more computers,
physically close together (usually in the same building), that are
linked to each other. LANs can contain devices other than
computers, for example, printers, print servers, storage devices,
etc.
If you're new to networking, there are many tutorials available
on the web to get you started. See this
page for links to them.
NOTE! Adding the second NIC is probably the most
difficult part of getting your Internet connection shared.
Many of the emails that I receive tell long tales of woe and
struggle with this step.
Nevertheless, it's important that you add that NIC! I've
put together a
page to help you through the process, so give it a
look.
Choose Your Connection
Method You first need to determine the type of
connection method to use for your network. During the past
year or so, new options have appeared, so let's summarize your
choices:
Let's do
Ethernet Ethernet has been the most common LAN
building method since it's been around the longest, so the rest of
this page will concentrate on the choices available in that
method. The downside of using Ethernet is that you need to run
special cabling in order to use it. If this will be a problem
for you, then you should head on over to the Alternative
Networking section and explore the other connection methods
that are now available.
This page from this Linksys article gives a short summary of
the two types of Ethernet cabling. Thin Ethernet (10base2) can run
at a maximum of 10Mbps, while the proper grade of UTP cable
can support up to 100Mbps operation. You'll need a 100MBps hub
and 100Mbps Network Interface Cards in order to take advantage of
the higher speed, both of which cost slightly more than 10Mbps
components. In most cases, a 10Mbps (10baseT) network will
work just fine.
Tip: Speeds up to 1Gbps (giga bits per second) are even
possible over "CAT5" cable with the newer "gigabit over copper"
Ethernet adapters!
Make sure you also take into account the maximum allowable
cable lengths in deciding which type of cabling to use:
Cable Type |
Max. Length |
10Base2
(Thinnet) |
600ft |
10BaseT
(UTP Category 5) |
328ft |
If you'd like more information on the Pros and Cons of the
various kinds of Ethernet cabling, check the Linksys article.
Is "Thin Net" for you? If you have
only a few machines and want to spend the minimum amount of money,
you can use 10base2 or "thinnet" or coaxial cabling to connect your
computers as shown in the diagram below. This method is less
expensive than using the 10baseT method (which I'll talk about
next), and contrary to some things you may read on the net, runs
at the same speed as 10baseT.
Note that cable modems don't support the 10base2 coaxial
cable, but use 10baseT instead. So you'll have to use UTP
(Unshielded Twisted Pair) cable (see explanation below) to make the
connection from the cable modem's RJ45 connector to the RJ45
connector on the first NIC in the Proxy computer.
Here's a cabling diagram of a simple network for sharing your
cable modem, if you want to use 10base2 cabling. Only
two computers are shown, but, of course, you can add more computers
by removing a terminator, connecting another computer as shown
below, and re-installing the terminator on the last computer in the
chain.
10BaseT for Me! If you have
more than one sharing Client, or are planning to expand your network
later, or have to run your cables in areas where they might be
damaged or tampered with, then you should use 10baseT cabling to set
up your network, as shown in the next diagram below.
Networking equipment manufacturers have made setting up a network
easier by bundling NICs, cables, a hub and setup documentation into
handy kits. This may be the way to go if you are setting up
your first network, but please read this
page on hubs before you buy one of these kits.
Note that you use a different kind of cable, called UTP
(Unshielded Twisted Pair), for a 10baseT network. Although it
may look like the cable that you use to connect your
telephone to the wall, it's not. So be sure to use the correct
cable to build your network. This kind of network also doesn't
need terminators.
Don't just connect everything to the
10baseT hub! Yes, I know all those jacks are inviting
and it seems so simple, but unless your cable company has assigned
you multiple IP numbers, it either won't work, or at some point will
stop working. For further explanation, see the Why
Two NICs? and How
a Hub Works pages.
Here's a cabling diagram of a simple network for sharing your
cable modem, if you want to use 10baseT cabling.
NOTE: If you follow the diagram below, do not connect
any cables into the hub's "uplink" port. That connector
is used to connect one hub to another, in case you need more
ports. (To "cascade" or "daisy chain" hubs, you would connect
the "uplink" port on one hub to a normal port on another hub, using
a regular UTP cable.)
10BaseT...with a "twist" If
you have only two computers in your network, you can get by without
a hub, if you use a special kind of UTP cable called a
"Crossover Cable". You can purchase them at the same place
that you buy normal 10baseT UTP cables, or make
one.
This network configuration is shown in the diagram below.
Note that many more configurations of LANs are possible,
including LANs that have both 10base2 and 10baseT sections (using
hubs that suppport both standards, such as the Netgear EN104).
So you've selected your type of network wiring, and maybe even
have things connected together. You now have to install and
configure your LAN (Local Area Network) software.
Let's
do it!
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