Refer to the exhibit. A new TAC engineer came to you for advice. A GRE over IPsec tunnel was configured, but the tunnel is not coming up. What did the TAC engineer configure incorrectly?
正解:B
Explanation/Reference: Explanation: The access-list must also support GRE traffic with the "access-list 102 permit gre host 192.168.1.1 host 192.168.2.1" command -> B is correct. Below is the correct configuration for GRE over IPsec on router B1 along with descriptions.