You work as an IT professional in an international corporation named Wiikigo. In the company, your job is to configure Microsoft Internet Security and Acceleration Server 2006. And you are experienced in performing and managing networks and operational systems. In addition, you are skilled at deploying ISA Server 2006, configuring firewall settings, and optimizing performance of the ISA Server 2006 cache. There is a main office in the company, and the company plans to add a branch office. There is an ISA Server 2006 computer in the main office and the new branch. You intend to utilize a site-to-site VPN to connect the main office and the branch office networks. A site-to-site VPN connection is created, and the company utilizes the L2TP over IPSec VPN protocol to connect the office networks. The company installs computer certificates on the ISA Server computer at each office. When the remote site network is created on each ISA Server computer, it is set to utilize certificates and a preshared key. The company sets the preshared key as the office name on the ISA Server computer at at each office. From the ISA Server computer at the main office, the ping command is repeatedly run to a host on the branch office network. The site-to-site VPN cannot work successfully. The Routing and Remote Access console is opened and the demand-dial interface is manually dialed. The following error message is displayed. The last connection attempt cannot work. A processing error is encountered by the security layer during initial negotiations with the remote computer, so that the L2TP connection attempt failed.
You are required to utilize the most secure IPSec authentication method possible to enable the site-to-site VPN connection.
Which action should be performed?
A.
The preshared key should be removed from the remote site network configuration on the ISA Server computer at both offices
B.
The remote site network should be deleted on the ISA Server computer at both offices, and the remote site networks with the original parameters should be recreated.
C.
The ISA Server computer at both offices should be restarted.
D.
The preshared keys should be re-entered on the ISA Server computer at both offices. And then, the preshared keys should be modified so that mixed-case letters, numbers, and symbols are contained.