A must read article related to evolution of firewalls.

This paper looks at the evolution of firewall technology towards Deep Packet Inspection, and then discusses some of the security issues with this evolving technology.
Topics covered in the article:
- Introduction
- Shallow Packet Inspection
- Medium Depth Packet Inspection
- Deep Packet Inspection
- Example Exploits
- Observations
- Conclusion

For reading full article visit http://www.securityfocus.com/infocus/1817