This chapter provided a very detailed overview of VPNs with a concentration on using IPSec as a VPN technology. It started by covering the various VPN components such as the Cisco Secure PIX Firewall, Cisco routers, and the Cisco VPN Concentrator. It then covered the technicalities of IPSec and the components that make up IPSec.
The chapter covered the five-step process of IPSec VPN establishment that includes IKE phase one and IKE phase two.
The chapter finished by looking at IPSec security associations (SAs) and also provided an overview of the certificate authority (CA) process.
Now that you have a foundation of knowledge on IPSec and VPN terminology, the next chapter looks at the individual VPN components and the configuration challenges that each one brings.