Firewalls are not new; but high-performance firewalls are. Historically, firewalls used software to examine every packet and then make the decision to forward or drop the packet. This made them slow. When administrators placed them in line with low-speed WAN access links, firewalls introduced no bottlenecks. But the trust boundary where a firewall is needed doesn't always lie at a WAN link. A finance department's network needs protection from disruption by other departments in the building.
Also, the speed of WAN links is increasing as the use of the Internet grows. Multigigabit links to metropolitan-area networks will become commonplace over the next few years. At these speeds, the performance bottleneck of older firewalls will be exposed.
News: Firewalls
