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Firewall

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									An Introduction to Firewalls
                            By:

        David Moss, NUIT Technology Support Services
Vince Celindro, NUIT Telecommunications and Network Services
Robert Vance, NUIT Telecommunications and Network Services
  Barbara Mims, Office of Alumni Relations and Development
                Agenda
• Firewall Basics for the Beginning User
• NUIT Firewall Offering
• Case Study – Desktop Firewall Software
  Implementation for the Office of Alumni
  Relations and Development
• Questions and Answers
         What is a Firewall?
• A firewall is hardware, software, or a
  combination of both that is used to prevent
  unauthorized programs or Internet users
  from accessing a private network and/or a
  single computer
Hardware vs. Software Firewalls
• Hardware Firewalls
  – Protect an entire network
  – Implemented on the router level
  – Usually more expensive, harder to configure
• Software Firewalls
  – Protect a single computer
  – Usually less expensive, easier to configure
How does a software firewall work?
• Inspects each individual “packet” of data
  as it arrives at either side of the firewall
• Inbound to or outbound from your
  computer
• Determines whether it should be allowed
  to pass through or if it should be blocked
             Firewall Rules
• Allow – traffic that flows automatically
  because it has been deemed as “safe”
  (Ex. Meeting Maker, Eudora, etc.)
• Block – traffic that is blocked because it
  has been deemed dangerous to your
  computer
• Ask – asks the user whether or not the
  traffic is allowed to pass through
What a personal firewall can do
• Stop hackers from accessing your
  computer
• Protects your personal information
• Blocks “pop up” ads and certain cookies
• Determines which programs can access
  the Internet
What a personal firewall cannot do
• Cannot prevent e-mail viruses
  – Only an antivirus product with updated
    definitions can prevent e-mail viruses
• After setting it initially, you can forget
  about it
  – The firewall will require periodic updates to
    the rulesets and the software itself
     Considerations when using
      personal firewall software
• If you did not initialize an action and your
  firewall picks up something, you should
  most likely deny it and investigate it
• It’s a learning process (Ex. Spooler
  Subsystem App)
• If you notice you cannot do something you
  did prior to the installation, there is a good
  chance it might be because of your firewall
      Examples of personal firewall
               software
•   ZoneAlarm <www.zonelabs.com>
•   BlackICE Defender <http://blackice.iss.net>
•   Tiny Personal Firewall <www.tinysoftware.com>
•   Norton Personal Firewall <www.symantec.com>

***Please be sure to read the license agreement
   carefully to verify that the firewall can be legally
   used at home and/or the office.
       Windows XP Firewall
• Currently *not* enabled by default
• Enable under Start -> Settings -> Control
  Panel
• Select Local Area Connection
• Select the Properties button
• Click the “Advanced” tab
Windows XP firewall
  Updates to Windows XP Firewall
• *Will* be enabled in default installations of
  Windows XP Service Pack 2
• Ports will be closed except when they are
  in use
• Improved user interface for easier
  configuration
• Improved application compatibility when
  firewall is enabled
           Mac OS X firewall
•   *Not* enabled by default
•   Enable under System Preferences
•   Select Sharing
•   Click “Firewall” tab
•   Click “Start” button
Mac OS X firewall
NUIT Firewall Service
           Why Netscreen?
• Comparison of the Big 3
  – Hardware vs. Software
  – Transparent Mode vs. Routing Mode
  – Distributed Management
  – Pricing Models
             The Process
• A Department requests a FW Consultation
• TNS Organizes a Meeting
• The Department Provides the List of
  Machines they want to Protect
• TNS Measures Bandwidth Requirements
• TNS Prepares a FW Proposal
• The Department Makes their Decision
           The Process continued...
•   TNS Installs the FW in a Passive State
•   TNS Logs All Traffic from the Target Hosts
•   TNS Develops a Rule Set
•   The Department Oks the Rule Set
•   TNS Activates the Rule Set
•   Everyone's Happy =)
              Final Notes
• Rule Management
• Default Allow vs. Default Deny
• Firewalls do NOT Solve the Entire Problem
              Additional Information
• Visit the following websites:
•   http://www.it.northwestern.edu/reference/firewall/firewall_strategies_wp.html
•   http://www.juniper.net/netscreen_com.html

• Or simply email:
     – nsg-net@northwestern.edu
     – consulting-services@northwestern.edu

								
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