单项选择题 You have a VPN server that runs Windows Server 2003 Service Pack 2 （SP2）. The VPN server supports only PPTP connections. A firewall protects the VPN server from the Internet. From a remote computer connected to the Internet， you attempt to connect to the VPN server. During the connection attempt， you receive a message that your user name and password are being verified. You then receive the following error message： “Error 721： The remote computer is not responding.”You need to ensure that you can establish a VPN connection to the VPN server from the Internet.  What should you do？（）

单项选择题 our company has a main office and one branch office. All servers run Windows Server 2003 Service Pack 2 （SP2）. The main office has a third-party gateway device named Gateway1.  Gateway1 is connected to the internal network and the Internet. Gateway1 supports IPSec. In the branch office， you have a server named Server1. You create an IPSec policy on Server1. You need to ensure that Server1 can establish an IPSec tunnel to Gateway1.  What should you use to configure the IPSec policy？（）

单项选择题 Your company has a main office and two branch offices. The main office is located in Montreal. The branch offices are located in Seattle and Winnipeg. In the Montreal office， you have a server named Server1 that runs Windows Server 2003 Web Edition Service Pack 2 （SP2）. Server1 is configured as a VPN router. In the Seattle office， you have a VPN server named Server2. In the Winnipeg office， you have a VPN server named Server3. On Server1， you configure a L2TP/IPSec demand-dial interface for each branch office. On each branch office server， you create a single demand-dial interface that uses L2TP/IPSec to connect to the main office. All demand-dial interfaces are configured to use a pre-shared key. You discover that only one branch office can connect to the main office at a time. You need to ensure that both branch offices can connect to the main office simultaneously.  What should you do？（）