What is Windows
Firewall?
A
firewall helps to
keep your computer
more secure. It
restricts
information that
comes to your
computer from other
computers, giving
you more control
over the data on
your computer and
providing a line of
defense against
people or programs
(including viruses
and worms) that try
to connect to your
computer without
invitation.
You can think of a
firewall as a
barrier that checks
information (often
called traffic)
coming from the
Internet or a
network and then
either turns it away
or allows it to pass
through to your
computer, depending
on your firewall
settings. See the
following
illustration:
In
Microsoft Windows XP
Service Pack 2 (SP2),
Windows Firewall is
turned on by
default. (However,
some computer
manufacturers and
network
administrators might
turn it off.) You do
not have to use
Windows Firewall—you
can install and run
any firewall that
you choose. Evaluate
the features of
other firewalls and
then decide which
firewall best meets
your needs. If you
choose to install
and run another
firewall, turn off
Windows Firewall.
How does it work?
When someone on the
Internet or a
network tries to
connect to your
computer, we call
that attempt an
"unsolicited
request." When your
computer gets an
unsolicited request,
Windows Firewall
blocks the
connection. If you
run a program such
as an instant
messaging program or
a multiplayer
network game that
needs to receive
information from the
Internet or a
network, the
firewall asks if you
want to block or
unblock (allow) the
connection. If you
choose to unblock
the connection,
Windows Firewall
creates an
exception so
that the firewall
won't bother you
when that program
needs to receive
information in the
future.
For example, if you
are exchanging
instant messages
with someone who
wants to send you a
file (a photo, for
example), Windows
Firewall will ask
you if you want to
unblock the
connection and allow
the photo to reach
your computer. Or,
if you want to play
a multiplayer
network game with
friends over the
Internet, you can
add the game as an
exception so that
the firewall will
allow the game
information to reach
your computer.
Although you can
turn off Windows
Firewall for
specific Internet
and network
connections, doing
this increases the
risk that the
security of your
computer might be
compromised.
What Windows
Firewall does and
does not do
|
It does: |
It does not: |
|
Help block
computer
viruses and
worms
from
reaching
your
computer. |
Detect or
disable
computer
viruses and
worms
if they are
already on
your
computer.
For that
reason, you
should also
install
antivirus
software and
keep it
updated to
help prevent
viruses,
worms, and
other
security
threats from
damaging
your
computer or
using your
computer to
spread
viruses to
others. |
|
Ask for your
permission
to block or
unblock
certain
connection
requests. |
Stop you
from opening
e-mail with
dangerous
attachments.
Don't open
e-mail
attachments
from senders
that you
don't know.
Even if you
know and
trust the
source of
the e-mail
you should
still be
cautious. If
someone you
know sends
you an
e-mail
attachment,
look at the
subject line
carefully
before
opening it.
If the
subject line
is gibberish
or does not
make any
sense to
you, check
with the
sender
before
opening it. |
|
Create a
record (a
security
log),
if you want
one, that
records
successful
and
unsuccessful
attempts to
connect to
your
computer.
This can be
useful as a
troubleshooting
tool. |
Block spam
or
unsolicited
e-mail
from
appearing in
your inbox.
However,
some e-mail
programs can
help you do
this. Check
the
documentation
for your
e-mail
program to
learn more. |
|
