This section discusses a number of case studies showing the implementation of the concepts discussed in this chapter. Configurations, debugs, and show command output are included to help you understand the contents better.
It would be very educational for you to compare the debug output with the earlier step-by-step explanation of IKE to try to understand where each IKE negotiation step takes place.
Router-to-Router IPsec Using Preshared Keys as the Authentication Mechanism
This is the most basic and common type of IPsec VPN. This VPN falls under the category of LAN-to-LAN VPNs. The authentication method used here is preshared keys. The following case studies have examples of more-secure authentication methods.
We will use this case ...