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Firewalls. Presented by: Sarah Castro Karen Correa Kelley Gates. Fundamentals of Firewalls. What is a firewall? A firewall is a software or hardware that prevents unauthorized access, and enforces an access control party between two networks.
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Firewalls Presented by:Sarah CastroKaren CorreaKelley Gates
Fundamentals of Firewalls • What is a firewall? • A firewall is a software or hardware that prevents unauthorized access, and enforces an access control party between two networks. • A firewall imposes its policy on everything behind it. • YOU – the user decides the policy
Why do we need a firewall? • To prevent certain types of data from getting in or out of particular areas • Security between the outside world and your network, especially protection from most Internet security threats • Firewalls keep damage on one part of the network
Security threats posed by the Internet Unauthenticated interactive logins Application backdoors SMTP session hijacking Operating system bugs Denial of service E-mail bombs Macros Viruses Spam Redirect bombs Source routing What does a firewall protect against?
What does a firewall not protect against? • Certain class of threats such as inside attacks, and Outside attacks that it cannot detect • Tunneling over most application protocols to trojaned or poorly written clients • Data-driven attacks- something is mailed or copied to an internal host where it is then executed. • Past occurrences against OutLook
OSI MODEL & FIREWALLSPacket Filter Firewalls • Work at network layer • Usually routers and firewall appliances • Scan IP header in rule base for: • Source IP address • Destination IP address • TCP/UDP source port • TCP/UDP destination port • Example on web
Circuit Level Gateways • Work in session layer of the OSI model (~ transport layer of the TCP/IP model) • Ensures that the session between two end users is legitimate • However, no further processing or filtering of individual packets is done.
Application Level Gateways • Work in application layer • Usually proxy servers, also personal firewalls • High level of security • Can slow down network • Example: Proxy Server and DMZ
Stateful Multilayer Inspection Firewalls • Combination of the above • High level of security, and good performance • Expensive • Complex
TYPES OF FIREWALLS Personal Firewalls • Software-only solutions • No external devices • Easy to install and upgrade • Protects against: • Worms, Trojan horses, and spyware • Examples: ZoneAlarm, BlackIce • Advantages, Disadvantages
Firewall Appliances • Specialized hardware devices, sometimes part of SOHO router • Can be Plug and Play • Provide NAT and TCP port inspection • DMZ • Example: NetGear, Linksys etc.
Turnkey Solutions • Turnkey solutions combine (arguably) the best of both Appliance and Software-only solutions • Wider range of services offered • More expensive, greater number of components
Differences between software and hardware firewalls On webpage: • Level of Protection • Manageability • Cost Analysis • Feature Set Comparison • Future Outlook • Grade Summary
REMEMBER • The use of firewalls presents a tradeoff between service and protection. • Decide what your optimal balance between security and service is!!!
Conclusion • Implementing a firewall is a great tool for security purposes BUT, DO EXPECT FAILURE PLAN FOR THE WORST
Q & A Questions?