Adaptive Security Appliance (ASA) by Arash Deljoo | Udemy

In computer networking, Cisco ASA 5500 Series Adaptive Security Appliances, or simply Cisco ASA, is Cisco’s line of network security devices introduced in May 2005.[1] It succeeded three existing lines of popular Cisco products:

• Cisco PIX, which provided firewall and network address translation (NAT) functions, ended its sale on July 28, 2008.
• Cisco’s IPS 4200 Series worked as intrusion prevention systems (IPS).
• Cisco VPN 3000 Series Concentrators, which provided virtual private networking (VPN).

The Cisco ASA is a unified threat management device, combining several network security functions in one box.

Cisco’s ASA is a set of stateful security appliances ranging from the model 5505, which is designed for Small Office, Home Office (SOHO) environments, to the 5580, which is designed for large enterprise networks and ISP sites. All of these products use the same operating system and management tools, easing your implementation and monitoring tasks.

Because all the security appliances use the same operating system, the major differences between the models primarily concern scalability and performance.

The ASA family of products (and their older siblings, the PIX products) can best be described as hybrid firewalls. Cisco, however, does not like to use the term “firewall” to describe the ASA and PIX product family. Instead, Cisco prefers using the term “security appliance,” mainly because the ASA products and the products they replaced, the PIX products, are not just stateful firewalls;