NETWORK SECURITY THROUGH FIREWALLS

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NETWORK SECURITY THROUGH FIREWALLS

• Caprice DiLiello
• Ron Kelley
• Liang Xu
• Steve Conwell
• Cynthia Reese

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INTRODUCTION

• What is a Firewall
• Wall used as a barrier
• Protects from intruders
• Examines traffic to see if it meets certain
  criteria
• Filters both inbound and outbound traffic
• Can be either a hardware device or a software
  program
• Discuss 3 Models
• Network Layer Firewall
• Application Level Gateway
• Stateful Inspection Firewall
• OSI Model

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OSI AND TCP/IP MODELS
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NETWORK LAYER FIREWALLS

• Packet Filtering
• Works at network layer or IP layer
• Part of a router
• Compared to a set of criteria

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NETWORK LAYER FIREWALLS

• Circuit Level Gateways
• Work at session layer or TCP layer
• Monitor TCP handshaking between packets

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Application Gateways

• First Firewalls
• Runs at the application layer of OSI model
• Application specific

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DUAL-HOMED GATEWAY
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STATEFUL INSPECTION FIREWALLS

• Filter packets at the network layer
• Evaluate contents of packets at the application
  layer
• Allow direct connection between client and host
• Use algorithms

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STATEFUL MULTI-LAYER INSPECTION FIREWALL
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FIREWALL SUMMARY

• COMPARE AND CONTRAST
• Packet Filter Application/Proxy Stateful
  Inspection
• Provides basic Extends packet filters
  Most flexible security
• access control
  solution
• Least secure of Effective security
  Effective security
• the three types solution
  solution
• Relatively Good security vs
  Highest initial cost
• inexpensive cost solution
  
• OVERVIEW