Implementing Cisco IP Routing (CCNP ROUTE, legacy) — Question 71

What are the four main steps in configuring a GRE tunnel over IPsec on Cisco routers? (Choose four.)

Answer options

• A. Configure a physical interface or create a loopback interface to use as the tunnel endpoint.
• B. Create the GRE tunnel interfaces.
• C. Add the tunnel interfaces to the routing process so that it exchanges routing updates across that interface.
• D. Add the tunnel subnet to the routing process so that it exchanges routing updates across that interface.
• E. Add all subnets to the crypto access-list, so that IPsec encrypts the GRE tunnel traffic.
• F. Add GRE traffic to the crypto access-list, so that IPsec encrypts the GRE tunnel traffic. ABDF

Correct answer:

Explanation

The correct steps for configuring a GRE tunnel over IPsec include establishing the necessary interfaces, integrating them into the routing process, and ensuring the traffic is encrypted. Options A, B, C, and F are essential for this configuration, while option D focuses on the subnet rather than the interfaces, and option E suggests adding all subnets, which is not specifically required for GRE tunnel establishment.