LANs, WANs, WLANs are known as edge networks May be contained within businesses or homes Needs to be protected from the rest of the Internet! Why firewall? Encryption? Cannot stop malicious packets from getting into an edge network Authentication? Can determine whether an incoming IP packet comes from a trusted user However, not all host computers have resources to run authentication algorithms Host computers managed by different users with different skill levels. | J. Wang. Computer Network Security Theory and Practice. Springer 2008 Chapter 7 Network Perimeter Security J. Wang. Computer Network Security Theory and Practice. Springer 2008 Chapter 7 Outline General Framework Packet Filters Circuit Gateways Application Gateways Trusted Systems and Bastion Hosts Firewall Configuration Network Address Translations Setting Up Firewalls J. Wang. Computer Network Security Theory and Practice. Springer 2008 LANs, WANs, WLANs are known as edge networks May be contained within businesses or homes Needs to be protected from the rest of the Internet! Why firewall? Encryption? Cannot stop malicious packets from getting into an edge network Authentication? Can determine whether an incoming IP packet comes from a trusted user However, not all host computers have resources to run authentication algorithms Host computers managed by different users with different skill levels. Overview J. Wang. Computer Network . | J. Wang. Computer Network Security Theory and Practice. Springer 2008 Chapter 7 Network Perimeter Security J. Wang. Computer Network Security Theory and Practice. Springer 2008 Chapter 7 Outline General Framework Packet Filters Circuit Gateways Application Gateways Trusted Systems and Bastion Hosts Firewall Configuration Network Address Translations Setting Up Firewalls J. Wang. Computer Network Security Theory and Practice. Springer 2008 LANs, WANs, WLANs are known as edge networks May be contained within businesses or homes Needs to be protected from the rest of the Internet! Why firewall? Encryption? Cannot stop malicious packets from getting into an edge network Authentication? Can determine whether an incoming IP packet comes from a trusted user However, not all host computers have resources to run authentication algorithms Host computers managed by different users with different skill levels. Overview J. Wang. Computer Network Security Theory and Practice. Springer 2008 General Framework J. Wang. Computer Network Security Theory and Practice. Springer 2008 What is a firewall? A hardware device, a software package, or a combination of both A barrier between the Internet and an edge network (internal network) A mechanism to filter Incoming (ingress) and outgoing (egress) packets. May be hardware and/or software Hardware is faster but can be difficult to update Software is slower but easier to update General Framework Firewall placement J. Wang. Computer Network Security Theory and Practice. Springer 2008 Chapter 7 Outline General Framework Packet Filters Circuit Gateways Application Gateways Trusted Systems and Bastion Hosts Firewall Configuration Network Address Translations Setting Up Firewalls J. Wang. Computer Network Security Theory and Practice. Springer 2008 Packet Filters Perform ingress (incoming) and egress (outgoing) filtering on packets Only inspect IP .
