One of the essential things we wanted to convey in this chapter is the importance of planning for your VPNs. When building VPNs, we recommend that you always keep in mind fundamental considerations, particularly scalability, interoperability, and key distribution. You also need to have a clear understanding of what topology is the best for your scenario, how packets are going to be routed, what parts of your network are protected, what are the possible points of failure, and so forth.
Once your VPN has been deployed, it is important to know how to maintain it. In this chapter, we described two common maintenance tasks: performance measurements and logging. In addition, you might want to consider other areas related to maintenance, including upgrades, adding new users, and defining security policies. The rest of this book will focus on the details of various VPN solutions and protocols. Use the knowledge from this chapter with the VPN solutions we describe to effectively deploy and maintain your VPN.