| 14.3 |  | Task 1 - Prepare to Configure VPN Support |
| 14.3.5 |  | Step 5 - ensure that the network works without encryption |

| A VPN tunnel can only operate over a correctly functioning network. If IPSec traffic is not working properly, the network must first be ruled out as a cause of the errors. The properties of VPN with encrypted traffic and multiple policies make troubleshooting very difficult. Traffic protocol analyzers or packet sniffers are generally made ineffective by IPSec as all information over Layer 3 in the OSI model is hidden. Multiple IPSec policies, IKE policies, and access lists can also cause network problems. Therefore, it is very important to make sure the network works before implementing VPN.

| Lab Activity e-Lab Activity: Task One - Prepare for IPSec Steps 3, 4, & 5 In this activity, students will learn how to avoid difficulties in configuration and testing.