单项选择题 Your company has a main office and 10 branch offices. Each office connects to the Internet by using a direct link.  The main office connects to the branch offices by using a WAN link. You plan to deploy Exchange Server 2010 servers in each office.  You need to design Active Directory to meet the following Exchange Server 2010 requirements：.Users must be able to access their mailboxes if a single domain controller fails .Users must be able to send e-mail messages to the Internet if a WAN link fails  What should you include in the design？（）

单项选择题 Cer-tech .com has an active directory domain. You are the administrator of ES1，a server that runs Windows Server 2008 and has Terminal Services role and the Terminal Services Web Access role serviceinstalled on it. You install Terminal Services Gateway role on ES1 and create the Terminal Services connection authorization policy. Users are reporting that they cannot access ES1. What should you do toensure that the users can connect to ES1？（）

单项选择题 You have a Class C network, and you need ten subnets. You wish to have as many addresses available for hosts as possible. Which one of the following subnet masks should you use?（）