Firewall. Ercan Sancar & Caner Sahin. 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. History Of Firewall.
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Firewall Ercan Sancar & Caner Sahin
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
History Of Firewall Firewall technology emerged in the late 1980s...
What is Firewall??? • A firewallis a piece of software or hardware...
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.
What Firewall Can’t Do??? • Inside attack! • Social engineering. • Viruses and Trojan horse programs. • Poorly trained firewall administrators.
A Firewall That Fits • Personal Firewall • Departmental or small organiztion Firewall • Enterprise Firewall
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
Basic Function of Firewall • Packet filtering • Network Address Translation(NAT) • Application Proxy
Working Principle of Firewalls • General Strategy: Allow-All or Deny-All • Filtering Properties
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.
Filetering Properties • Packet Filtering • Network Address Translation(NAT) • Application Proxy
Packet Filtering • What is Packet Filtering? • Filtering IP data.
Network Address Translation(NAT) • What is NAT? • Security Aspects of NAT. • Consequences of NAT.
Application Proxy • What is Application Proxy • Differnce between Application Proxy and Packet Filtering • Advantages of Application Proxy • Drawbacks of Application 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 Comparison of NAT & Proxy NAT Proxy
Can a Firewall Really Protect Me? A firewall is indeed a very effective method of protection against many of these threats, but...
Multiple Firewall • When Two Firewall Are Better Than One • Designing Demilitarized Zones(DMZ)
Advantages of DMZ with Two Firewall • Clear Definition of The DMZ • Increased Security • Reduce Network Loads on the Two Firewalls
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
Firewall Functions in Windows • Packet Filtering • Network Address Translation(NAT/ICS) • Encrypted Tunnel
Firewall Functions Which is not provide in Windows • No application Proxies • No (or less-than-ideal)monitoring and logging • No data caching
Choosing a Firewall That Meets • How do you decided? • What compare?