Network Security: Network Security: FirewallsFirewalls

MIS 5973 – InfrastructuresMIS 5973 – Infrastructures

Summer 2002 – Kelly S. NixSummer 2002 – Kelly S. Nix

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

The Threats

Denial-of-ServiceUnauthorized AccessExecution of Unauthorized CommandsBreaches of ConfidentialityDestructive Behavior

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

Basic Security

Backup, Backup, BackupControl Where Data Is LocatedDecentralize Your Security SystemYour Operating System May Not Be Your Friend

Firewalls: Locking Out The World

Firewall Terminology

Bastion HostRouterAccess Control List (ACL)Demilitarized Zone (DMZ)ProxyStateful InspectionNetwork Address Translation (NAT)

Hardware Firewall

Software Firewall

How It Works

Firewalls & the OSI