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？（）

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？（）