单项选择题 Your network contains a domain controller that is configured as a DNS server. The server hosts an  Active Directory-integrated zone for the domain.   You need to reduce how long it takes until stale records are deleted from the zone.  What should you do（）

单项选择题 Your network contains an Active Directory domain named contoso.com. The domain contains the servers shown in the following table.   Server name  Operating system  Role   DC1  Windows Server 2008  Domain controller    DC2  Windows Server 2008 R2  Domain controller    DNS1  Windows Server 2008  DNS server  DNS2  Windows Server 2008 R2  DNS server   The functional level of the forest is Windows Server 2003. The functional level of the domain is Windows  Server 2003.   DNS1 and DNS2 host the contoso.com zone.   All client computers run Windows 7 Enterprise.   You need to ensure that all of the names in the contoso.com zone are secured by using DNSSEC.  What should you do first（）

单项选择题 Your company has a main office and a branch office.   The network contains an Active Directory domain named contoso.com. The DNS zone for contoso.com is  configured as an Active Directory-integrated zone and is replicated to all domain controllers in the  domain.   The main office contains a writable domain controller named DC1. The branch office contains a read-only  domain controller （RODC） named RODC1. All domain controllers run Windows Server 2008 R2 and are  configured as DNS servers.   You uninstall the DNS server role from RODC1.   You need to prevent DNS records from replicating to RODC1.  What should you do（）