PUBLICATION & RESEARCH LIBRARY

Authors: NSS Labs

Publish Date: June 9, 2016

Firewall technology is one of the largest and most mature security markets. Firewalls have undergone several stages of development, from early packet filtering and circuit relay firewalls to application layer (proxy-based) and dynamic packet filtering firewalls. Throughout their history, however, the goal has been to enforce an access control policy between two networks, and thus firewalls should be viewed as an implementation of policy.