Once you have a firewall
in place, you should test it. A great way to do this is to go to <www.grc.com>
and try their free 'Shields Up!' security test. You will get immediate
feedback on just how secure your system is!
If you have been using the Internet for any length of time, you
have probably heard the term 'firewall'. For example, you often
hear people say things like, "I can't use that site because
they won't let it through the firewall".
a firewall is a barrier to keep destructive forces away from your
property. A firewall in computing terms is simply a program or hardware
device that filters the information coming through the Internet
connection into your private network or computer system.
let's consider a network with hundreds of computers that are connected
to each other and to the Internet. These machines will be connected
with network cards and it may have a couple of high-speed internet
connections. Without a firewall in place, all of those hundreds
of computers are directly accessible to anyone on the Internet.
A person who knows what he or she is doing can try to make FTP or
telnet connections to them and so on. If someone makes a mistake
and leaves a security hole, hackers can get to the machine and exploit
With a firewall
in place at every connection to the Internet, it can implement security
rules. For example, one of the security rules inside the company
Out of all
the computers inside this company, only one of them is permitted
to receive public FTP traffic.
You can set
up rules like this for your servers then you can control how others
connect to Web sites, whether files are allowed to leave the network,
and so on. A firewall gives you tremendous control over how people
use the network.
one or more of three methods to control traffic flowing in and out
of the network. They are:
1. Packet filtering
- Packets (small chunks of data) are analyzed against a set of filters.
2. Proxy service
- Information from the Internet is retrieved by the firewall and
then sent to the requesting system and vice versa.
inspection - A newer method that doesn't examine the contents of
each packet but instead compares certain key parts of the packet
to a database of trusted information.
customizable. You can add or remove filters based on several conditions
such as IP addresses, Domain names and Protocols.
firewall can be installed on the computer that has an Internet connection.
This computer is considered a gateway because it provides the only
point of access between your network and the Internet.
With a hardware
firewall, the firewall unit itself is normally the gateway. You
configure a router via a Web-based interface that you reach through
the browser on your computer. You can then set any filters or additional
information. Hardware firewalls are incredibly secure and inexpensive.
One of the
best things about a firewall from a security standpoint is that
it stops anyone on the outside from logging onto a computer in your
is a big deal for businesses, most home networks will probably not
be threatened in this manner. Still, putting a firewall in place
provides some peace of mind. After all, what is a network with thousands
of computers worth if you don't have peace of mind at the end of
the day? Don't hesitate to write in and share your views.
Very often, you may receive emails that either warn you about a
virus or simply urge you to forward a message to as many others
Some of these
are malicious, and some are not, but almost all of them are pranks
because they cause damage or loss to the rest of the Internet community
in some way. This is true most of the time, not always. You may
get a nice, touching message which insists that you forward it to
twenty or thirty people.
If you want
to do that fine, but doing it without any purpose causes Internet
traffic to increase. Imagine what would happen if every email user
started doing that.
one person sends it to ten people, they in-turn send it to ten others
and this keeps multiplying until it may gain enough momentum to
clog the whole Internet! This may not happen practically all the
time, but theoretically it could be quite devastating. So you can
do your best not to get 'hooked on' to such silly habits.
The facts about
virus warnings though, are a bit more serious. To begin with, go
to the official web site of MacAfee, Norton or any other site of
a reputed anti-virus expert and register with your email address
to receive regular newsletters about the latest viruses. They provide
authentic information about viruses and their cures, so you will
have nothing to worry about.
that, do not trust any other email that tells you of a virus in
your computer. If you get such a letter, first check to see whether
it contains a valid link to an authentic web site maintained by
an anti-virus expert and check to see if that link directs you to
the relevant information. If it doesn't, just delete the email because
chances are that the very email could have a virus attached to it!
One of the
key features of these hoax warnings is that they urge you to inform
everybody else in your address book about the threat of a virus.
Some of them seem real because they tell you of the exact location
of the virus within your computer and when you go there, you actually
see a file with a 'funny' icon which you are made to believe is
a virus and thus delete it.
These are mostly
system files that are vital for the operating system to function
properly and once deleted, you could be in serious trouble.
So as a rule
of thumb, take another look at those emails that ask you to forward
them to so many people, and analyze their contents. If it is something
unimportant or if it is a virus warning, delete it. If not do whatever
you want with it, but don't forward them to avoid bad luck or whatever
they claim to bring with them because you could just be bringing
bad luck to yourself and many others on the Internet by doing so.