Dr. Tom Shinder's ISA Server 2006 Migration Guide

Chapter 7. ISA 2006 Stateful Inspection and Application Layer Filtering

Solutions in this chapter:

• Application Filters

• Web Filters

Summary

Introduction

The ISA firewall is able to perform both stateful filtering and stateful application layer inspection. Its stateful filtering feature set makes it a network layer stateful firewall in the same class as any hardware firewall that performs stateful filtering at the network and transport layers. Stateful filtering is often referred to as stateful packet inspection, which is a bit of a misnomer because packets are Layer 3 entities, and to assess connection state, Layer 4 information must be assessed.

However, ...