Virtual Private Networks

Virtual private networks (VPNs) have become a crucial portion of nearly all enterprise
networks. The ability of VPN technologies to create a secure link interconnecting offices
over the Internet saves companies the expense of dedicated connections. Additionally, VPN
connections allow remote users to connect to their headquarters securely.
How to Best Use This Chapter
This chapter provides an overview of the different VPN technologies available and
discusses where the Cisco PIX Firewall can be used as an endpoint for VPNs. You need to
become very familiar with the methodology used to implement VPNs and how that methodology
is applied to the PIX. As you read through this chapter, consider how encryption
technology is applied in general, and then focus on the configuration steps required to
configure the PIX. If you are at all familiar with configuring VPNs on any Cisco product,
you will probably find this chapter very easy.
“Do I Know This Already?” Quiz
The purpose of this quiz is to help you determine your current understanding of the topics
covered in this chapter. Write down your answers and compare them to the answers in
Appendix A. If you have to look at any references to correctly answer the questions about
PIX functionality, you should read that portion and double-check your thinking by
reviewing the Foundation Summary. The concepts in this chapter are the foundation of
much of what you need to understand to pass the CSPFA Certification Exam. Unless you
do exceptionally well on the “Do I Know This Already?” pretest and are 100% confident in
your knowledge of this area, you should read through the entire chapter.
1 Which encryption is stronger, Group 2 Diffie-Hellman or 3DES?
2 What is the command to apply an access list to a crypto map?
3 What is the difference between ESP and AH?
4 What service uses UDP 500?