* The direction of traffic (inbound or outbound)
* Packet information such as the source or destination IP address or port number * The action to take when the traffic matches the filter criteria * Firewalls do not offer protection against all attacks (such as spoofed e-mail messages). The following table explains different firewall types.
Firewall Type| Characteristics|
Packet filtering firewall| A packet filtering firewall makes decisions about which network traffic to allow by examining information in the IP packet header such as source and destination addresses, ports, and service protocols. A packet filtering firewall: * Uses access control lists (ACLs) or filter rules to control traffic. * Operates at OSI layer 3 (Network layer). * Offers high performance because it only examines addressing information in the packet header. * Can be implemented using features that are included in most routers. * Is a popular solution because it is easy to implement and maintain, has a minimal impact on system performance, and is fairly inexpensive. A packet filtering firewall is considered a stateless...