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INTERNET CONNECTIONS
A hardware-based router
by Chris Taylor
I have written
several articles over the past year or two on
sharing an Internet connection using software-based
NAT (Network Address Translation) products, such
as SyGate and WinRoute Pro (see webref 1 below) As well, I
have written about how these products, as well as
some others, such as BlackICE Defender help
prevent intruders from attaching to your computer
and doing horrible things (see webref
2 below).
If you have a high-speed
connection to the Internet through cable modem or
DSL (such as Sympatico's High Speed Edition),
there is another solution you can go with - a
hardware-based router.
There is a relatively new category
of routers that have come onto the market recently that
are designed and priced for the home user. There are two
main benefits to using a hardware-based solution. First,
if you are trying to connect multiple machines to the
Internet, a software-based NAT solution requires that one
machine always remain on to provide the Internet
connection. With a hardware-based solution, only the
router needs to remain turned on. Second, from a security
perspective, it is generally more reliable to have a
piece of hardware as a buffer between your computers and
the Internet, rather than just software.
I recently helped a relative configure
one of these routers and am very impressed with it. The
router is the Linksys EtherFast Cable/DSL Router. There
are three models to choose from. Model BEFSR81 has an 8-port
10/100Mb/sec switch built in for connecting up to eight
computers together on a LAN. Model BEFSR41 has a 4-port
switch. Model BEFSR11 has a single port and may be used
if you have only a single computer or if you already have
a hub or switch. Other than the different number of
ports, the three models are functionally equivalent.
The 45-page manual is quite clear and
steps you through the process of installation and
configuration. It assumes you already have the network
cards installed in each of your computers. It then walks
you though the physical connections.
The router has a built-in web server and
it is through it that you configure the router. The
manual assumes you have configured the TCP/IP protocol on
your computer to use DHCP. If you have not, you must
ensure that your computers are using IP addresses in the
range 192.168.1.2 through 192.168.1.254 and your subnet
mask is set to 255.255.255.0. Other-wise, you will not be
able to access the router. This information is detailed
in the Trouble-shooting section of the manual. I wonder
how many people struggle with this step before figuring
out how it has to be configured.
Once you connect with your browser, you
are prompted to log into the router with a default
password, which can be changed later. There are a number
of screens you can access for various configuration
options.
On the main Setup screen you can change
the LAN IP address of the router from the default 192.168.1.1.
Normally there is no need to do so. For the WAN side of
the router, you specify the IP address assigned to you by
your ISP. If your ISP uses DHCP, you make the selection
Obtain an IP Address Automatically. Enter the IP
Addresses for the DNS servers, as provided by you ISP. If
you are using Sympatico's High Speed Edition, enable the
option for PPPoE and enter the username and password
assigned by Sympatico. Do not install the software that
Sympatico provides for connecting. It is not required and
will actually cause you problems if you try to use it.
On the DHCP tab, you can tell the router
if you want it to assign IP addresses for all the
machines on your network. If you have manually configured
TPC/IP on your machines, you can skip this step. Make
sure that if you use DHCP for any machine on your
network, you use it for all machines to prevent IP
address conflicts.
Once these two configuration screens have
been set, any computer on your network should be able to
access the Internet The router takes care of the details
of connecting, as well as the address translation between
your private IP addresses and the single public IP
address provided by your ISP.
After you have verified that things are
working right, it is a good idea to connect to the router
again and continue with some additional configuration
options.
You can use the Filters page to block
certain machines on your network from accessing the
Internet. You an either block complete access by entering
an IP address of a machine on your local LAN or just a
port number. For example, by entering port 80, you would
effectively block anyone from accessing the Web. Also on
this page is an option Block WAN Request. By toggling
this on, you are telling the router not to respond to
pings or connection requests from the Internet. This
effectively makes your router disappear from the Internet
- a great security feature.
There are times when you want someone on
the Internet to be able to access one of the computers on
your LAN. Normally, when using NAT, this is not possible
because your computers are assigned what is known as
private IP addresses and the Internet routers simply
refuse to route packets to such addresses. However, the
router permits this functionality through what it terms
Forwarding. What this does is instruct the router that
incoming packets to a particular port should be forwarded
on to a specific IP address on your LAN. You can
configure up to ten ports in this manner.
For example, if you're running a web
server on your machine that is configured as 192.168.1.30,
you configure the router to forward connection requests
on port 80 to that address. For another example, some
Internet-based games require that your computer listen on
a particular port. If running such a game, you have to
configure the router to forward requests on that port to
the computer on your LAN running the game.
A DMZ configuration option in the router
allows you to configure a single computer on your LAN to
accept all inbound connection requests. As such, it is
totally exposed to the Internet. While this is useful in
a few circumstances, unless you know why you are doing
it, you should normally avoid doing this. There are
additional configuration screens for dynamic and static
routing. Most people will not have to worry about these.
All in all, I am very impressed with the
Linksys EtherFast Cable/DSL Router. It is quite simple to
set up and has pretty much all the configuration options
most people will need. After several weeks of use, the
only problem that cropped up was one time when the router
went haywire and refused to route any packets. Powering
the router off and back on again fixed the problem.
After 10 minutes on the web and 5 minutes
on the phone, the best local prices I found were $180 for
the 1-port version, $270 for the 4-port version, and $365
for the 8-port version.
Webrefs:
1. opcug.ca/Reviews/sygate.htm
and opcug.ca/Reviews/winroute.htm.
2. opcug.ca/Reviews/blackice.htm
opcug.ca/Reviews/zonealar.htm,
and
opcug.ca/Reviews/sscan.htm
Originally published: February, 2001
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