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    FireWall FireWall Presentation Transcript

    • 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 ?
    • 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.
    • 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
    • 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
    • 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 
    • Types of FireWall Techniques
      • Packet filter
      • Application gateway (a.k.a. Proxy server)
      • Circuit-level gateway
      • Bastion Host
    • 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
    • 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
    • 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.
    • 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.
    • Conclusion
      • What a firewall can do ?
      • What a firewall cannot do ?
    • 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 .
    • 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
    • SECURED Firewall Thank You…… Source – >CNS Text Book (William Stallings) > Wikipedia