What Is a Firewall ?

•A firewall is an access control device that looks at the IP packet,compares with policy rules and decides whether to allow, deny or take some other actions on the packet  .

ASA Overview

• ASA = Adaptive Security Appliance that runs Adaptive Security Algorithm
• Stateful architecture is about flows or connections, not packets
   o Most effective with TCP, UDP, and ICMP
   o TCP is the main reason for deploying a stateful firewall
• Acts as a segregation gateway between networks, enforcing selective connectivity policies
• Tracks all packets as part of a stateful connection; blocks packets not part of a connection, and performs atomic security checks
• Performs network address translation (NAT); applies NAT to embedded application protocol data
• Inspects some application traffic flows for higher level protocol conformance and deep-packet inspection
• Integrates with other solutions (Unified Communications technologies, scansafe, etc.)