Network%20Security:%20Firewalls

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Network Security Firewalls

• MIS 5973 Infrastructures
• Summer 2002 Kelly S. Nix

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The only safe computer is a dead computer...
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The Threats

• Denial-of-Service
• Unauthorized Access
• Execution of Unauthorized Commands
• Breaches of Confidentiality
• Destructive Behavior

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Who Are These Guys?

• activists
• club initiates
• competitors
• consultants
• crackers for hire
• crackers
• customers
• cyber-gangs
• deranged people
• drug cartels
• economic rivals
• extortionists
• foreign agents and spies

• Fraudsters
• global coalitions
• government agencies
• hackers
• hoodlums
• Industrial espionage experts
• information warriors
• infrastructure warriors
• insiders
• maintenance people
• military organizations
• nation states
• nature

organized crime paramilitary groups police
private investigators professional thieves
reporters terrorists tiger teams vandals
vendors whistle blowers
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Basic Security

• Backup, Backup, Backup
• Control Where Data Is Located
• Decentralize Your Security System
• Your Operating System May Not Be Your Friend

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Firewalls Locking Out The World
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Firewall Terminology

• Bastion Host
• Router
• Access Control List (ACL)
• Demilitarized Zone (DMZ)
• Proxy
• Stateful Inspection
• Network Address Translation (NAT)

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Hardware Firewall
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Software Firewall
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How It Works
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Firewalls the OSI
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