Download Firewalls

Firewalls
CS158B
Don Tran
What is a Firewall?
• A firewall can be a program or a device that
controls access to a network.
Why do I need a Firewall?
• The Internet is a very dangerous place.
• Need to have a way of controlling what
gets into and out of your network.
• Firewalls also give you detailed
information of the kind of traffic passing
through your network.
How do Firewalls work?
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There are different types of Firewalls.
Some operate at the network layer.
Others operate at the application layer.
The higher the level the more security the
firewall offers.
Network Layer Firewalls
• The most common
network layer firewall
is the router.
• Filters out traffic
based on source and
destination IP
addresses and ports.
• Usually fast and
operate transparently
to the user.
Application Layer Firewall
• These are usually
hosts that are running
proxy servers.
• Proxy servers allow for
indirect connections
between a network and
the Internet.
• Slower than a Network
Firewall, but offers
more protection.
Windows Firewall
• Windows XP comes with its own firewall
service known as Windows Firewall.
• Protects your network by blocking
unsolicited requests to connect to your
network.
• Makes managing a firewall easy.
How to configure Windows Firewall
• Although blocking unsolicited requests is
good…
• Sometimes you may want to allow access
to your computer.
• Examples are Instant Messengers, and
some video games may require that other
computers connect to your computer.
Configuring Windows Firewall
• The first time that your run an application that
requires information from the Internet a window
will pop up.
Configuring Windows Firewall
• To access Windows Firewall’s settings:
• 1) Click on the “Start” menu button.
• 2) Navigate to “Control Panel”.
• 3) Click on “Windows Firewall”.
Configuring Widows Firewall
Windows Firewall Settings
• Turns Windows
Firewall on and off.
• Turns Exceptions on
and off.
Exceptions Tab
• Add and remove
exceptions.
• Open specific ports.
• Edit current
exceptions.
Edit Options
Advanced Tab
• Open and close ports
for specific
connections.
Important Notes
• There are always security risks involved with
allowing exceptions.
• Following these rules will help minimize those
risks:
• 1) Only allow exceptions if you need it.
• 2) Don’t allow an exception for a program that
you do not recognize.
• 3) Remove exceptions when you’re done with
them.