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FireWall

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Transcript

  • 1. FIREWALL
  • 2. Contents
    • What is FireWall ?
    • - Software vs. Hardware Firewall
    • How does FireWall works ?
    • Types of FireWall Techniques –
    • > Packet filter > Application gateway
    • > Circuit level gateway > Bastion host
    • Conclusion:
    • - What FireWalls can do ?
    • - What FireWalls cannot do ?
  • 3. What is FireWall ?
    • FireWall is device that provides secure connectivity between networks (internal/external).
    • A firewall may be a 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.
  • 4. Software vs. Hardware Firewalls Software Firewall Hardware Firewall
      • -Protect a single computer
      • -Usually less expensive, easier to configure
      • -Protect an entire network.
    • -Usually more expensive, harder to configure
    Norton Internet Security Cisco PIX Mcafee Internet Security NetScreen Outpost WatchGuard Ms. ISA Server Check Point
  • 5. How does a Firewall work?
    • Inbound to or outbound from your computer.
    • Inspects each “ packet ” of data that arrives at either side of the firewall.
    • Determines whether it should be allowed to pass through or if it should be blocked .
    sent sent received received packets packets
  • 6. How a firewall works ?
    • Sniffing Mode
    • An attacker tries to compromise a service on the protected network.
    • 2) The Firewall identifies the attempt .
    • The FIREWALL can now:
      • Alert the admin
      • Harden the firewall
      • Or reset a TCP/IP connection
    LOG Alert Reset Fire Wall 
  • 7. Types of FireWall Techniques
    • Packet filter
    • Application gateway (a.k.a. Proxy server)
    • Circuit-level gateway
    • Bastion Host
  • 8. Packet filter - It looks at each packet entering or leaving the network and accepts or rejects it based on user-defined rules . Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing . Packet Filtering Applications Presentations Sessions Transport DataLink Physical DataLink Physical Router Applications Presentations Sessions Transport DataLink Physical Network Network
  • 9. Application gateway Application gateway (Proxy Server)- User uses TCP/IP applications, such as FTP and Telnet servers. This is very effective, but can impose a performance degradation. Applications Presentations Sessions Transport DataLink Physical Network DataLink Physical Applications Presentations Sessions Transport DataLink Physical Application Gateway Applications Presentations Sessions Transport Network Network Telnet HTTP FTP
  • 10. Circuit-level gateway
    • Circuit-level gateway- It is a stand alone application.
    • It does not permit end-to-end TCP connection. It sets up 2 TCP connections:
    • > B/w itself and a TCP user on an inner host.
    • > B/w itself and a TCP user on an outer host.
  • 11. Bastion host
    • > Bastion host is a special purpose computer on a network specifically designed and configured to withstand attacks .
    • > It generally hosts a single application , provides platform for Application gateway and Circuit-level gateway. It supports limited/specific applications to reduce the threat to the computer. Include applications- Telnet,SMTP,FTP.
  • 12. Conclusion
    • What a firewall can do ?
    • What a firewall cannot do ?
  • 13. 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.
    • Block invalid packets .
  • 14. 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 cannot forget about it
      • The firewall will require periodic updates to the rulesets and the software itself.
    Virus can jump Firewall !! F I R E W A L L Deadly Virus
  • 15. SECURED Firewall Thank You…… Source – >CNS Text Book (William Stallings) > Wikipedia

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