Intro. to Personal Firewalls

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Intro. to Personal Firewalls
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Outline

• What is a firewall
• Types of firewalls
• Why need personal firewall
• What personal firewall can do
• What personal firewall cant do
• Personal firewall software introduction
• Reference

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What is a firewall?
WHO ? WHEN ? WHAT ? HOW ?
INTERNET
Secure Private Network
Firewall
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Whats a personal firewall

• Personal firewalls are software-only firewalls
  that run on the computer they protect.
• Designed for individual users or small networks.
• (eg.Windows XP comes with a personal firewall)
• Inexpensive and easy to install and use, should
  offer clearly explained configuration options.
• Allow the user to access all necessary network
  and web resources, protect from external
  "hacking" and alert the user to malicious
  activity.

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Why use a personal firewall

• Now that "always-on" broadband connections such
  as cable modems and xDSL are becoming more
  popular, home users are at risk.
• Protect your computer from network attacks when
  connected to the Internet.
• Stop malicious back door programs like
  BackOrificeor Trojan Horse from connecting to
  remote systems.
• To ensure that your computer does not participate
  in the denial-of-service attack on the Internet.
  
• Stop hackers from gaining personal information,
  such as credit card numbers, network
  passwordetc.

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What a personal firewall can do

• To prevent unauthenticated users from accessing
  the internet.
• Providing a single "choke point" where security
  and auditing can be imposed.
• Stop back door programs from connecting to remote
  systems.
• Content Filter/Monitor for dangerous scripts or
  programs

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What personal firewall cant do

• Cannot protect against attacks that don't go
  through the firewall.
• Cannot protect against a data-driven attack or
  things like viruses.
• Cannot stop attacks from malicious insiders that
  have direct access to your machine

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Ports

• Ports are doors into your computer that lead to
  a particular service
• There are 65 thousand ports in TCP/IP
• 1024 are well defined
• The port number along with the IP address is
  called a socket
• PFWs can be configured to close unneeded ports

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TCP Ports Identify the App
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Stateful inspection

• Look at outbound connection request to the
  Internet
• Remember the addresses and the ports
• Only permit traffic from the Internet if it saw
  that it was initiated from the inside network
• All modern firewalls work this way

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Personal firewall software introduction

• Freeware
• ZoneAlarm 5.1
• Sygate Personal Firewall 5.5
• Payware
• Norton Personal Firewall 2003
• Comparison

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Windows XP Firewall

• Currently enabled when SP2 is installed
• Remote Assistance is enabled by default
• Configure under Start Control Panel
• Can set exceptions for trusted programs or ports
• Can keep logs of activities
• Ports will be closed except when they are in use
  (statefull)

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Mac OS X firewall

• Not enabled by default
• Enable under System Preferences
• Select Sharing
• Click Firewall tab
• Click Start button

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Mac OS X firewall
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Zone Alarm v3.1
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Sygate Personal Firewall v5.0
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Sygate Personal Firewall v5.0
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Norton Personal Firewall 2003

• Visual Tracking

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Norton Personal Firewall 2003
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Reference

• Building Internet Firewalls , 2nd Edition /
  OREILLY June 2000By Elizabeth
  D. Zwicky, Simon Cooper, D. Brent Chapman
• Firewall QAhttp//www.vicomsoft.com/knowledge/re
  ference/firewalls1.html
• Home PC Firewall Guidehttp//www.firewallguide.co
  m/

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Reference

• ZoneAlarm 5.1 (Freeware)
• http//www.zonelabs.com/store/content/home.jsp
• Sygate Personal Firewall 5.5 (Freeware)
• http//soho.sygate.com/
• Norton Personal Firewall 2003 (Payware)
• http//www.symantec.com/sabu/nis/nis_pe/