1. Firewall Ercan Sancar & Caner Sahin

2. Index History of Firewall Why Do You Need A Firewall Working Principle Of Firewalls Can a Firewall Really Protect Me? Multiple Firewalls Firewall Functions in Windows Choosing a Firewall that Meets

3. History Of Firewall Firewall technology emerged in the late 1980s...

4. Why Do you Need a Firewall?

5. What is Firewall??? A firewall is a piece of software or hardware...

6. What Firewall Do??? Block incoming network traffic based on source or destination. Block outgoing network traffic based on source or destination. Block incoming network traffic based on content. Make internal resources available. Allow connections to internal network. Report on network traffic and firewall activities.

7. What Firewall Can’t Do??? Inside attack! Social engineering. Viruses and Trojan horse programs. Poorly trained firewall administrators.

8. A Firewall That Fits Personal Firewall Departmental or small organiztion Firewall Enterprise Firewall

9. Some Firewall Rules Allow everyone to access all Web Sites Allow outgoing e-mail from the internal mail server Drop all outgoing network traffic unless it mathces the first two rules Allow incoming Web request to the public Web server Drop all incoming network traffic expect for connections to the public Web server Log all connection attempts that were rejected by the firewall Log all access to external Web sites

10. Basic Function of Firewall Packet filtering Network Address Translation(NAT) Application Proxy

11. Working Principle of Firewalls General Strategy: Allow-All or Deny-All Filtering Properties

12. General Strategy of Firewall Allow-all Strategy:Allow all network packets except those that are explicitly denied. Deny-all Strategy:Denies all network packets except those that are explicity allowed.

13. Example Firewall Rules

14. Filetering Properties Packet Filtering Network Address Translation(NAT) Application Proxy

15. Packet Filtering What is Packet Filtering? Filtering IP data.

16. Example of Fragment

17. Stateful Packet Filtering What is a stateful inspection?

18. Network Address Translation(NAT) What is NAT? Security Aspects of NAT. Consequences of NAT.

19. Application Proxy What is Application Proxy Differnce between Application Proxy and Packet Filtering Advantages of Application Proxy Drawbacks of Application Proxy

20. Comparison of NAT & Proxy Network and Transport layer Not concerns with contents Users don’t need any settings Every program uses the same Application Layer Interface with the content Users need to setup the settings Differnt programs can use differnt proxies ProxyNAT

21. Can a Firewall Really Protect Me? A firewall is indeed a very effective method of protection against many of these threats, but...

22. Multiple Firewall When Two Firewall Are Better Than One Designing Demilitarized Zones(DMZ)

23. Designing Demilitarized Zones

26. Advantages of DMZ with Two Firewall Clear Definition of The DMZ Increased Security Reduce Network Loads on the Two Firewalls

27. Disadvantages of DMZ with Two Firewall Increased Cost Extra Training Required Multiple Firewall Rule Listing Must be Maintained Configuration Complexity When more Than Two Firewall are Deployed

28. Firewall Functions in Windows Packet Filtering Network Address Translation(NAT/ICS) Encrypted Tunnel

29. Firewall Functions Which is not provide in Windows No application Proxies No (or less-than-ideal)monitoring and logging No data caching

30. Choosing a Firewall That Meets How do you decided? What compare?

31. Thank you For Listening