Firewall Planning and Design

Networking and Security Topics for CISSP Study

Cryptographic Lifecycle

Firewalls are a vital part of your business defense, designed to enable authorized traffic to pass through and block unauthorized traffic, preventing business threats.

Without proper deployment and implementation, however, they bring relatively small value. Firewall are imperfect and only work when they are part of a Defense in Depth (DiD) network security approach.

Background, Firewalls In General

In general, a firewall is anything, whether hardware or software (or a combination of hardware and software), that can filter the transmission of packets of digital information as they attempt to pass through a boundary of a network. Firewalls perform two basic security functions:

Packet filtering: First and foremost, a firewall must be able to determine whether to allow or deny the passage of packets of digital information, based on established security policy rules.

Application proxy: In some cases, a firewall may provide network services to users while shielding individual host computers. This is done by breaking the IP flow (which is the traffic into and out of the network) between the network being protected and the network outside.

Firewall Security Features


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