单项选择题
A.Run the dnscmd . /clearcache command on Server3.
B.Run the ipconfig /flushdns command on Server3.
C.Decrease the Time-to-Live （TTL） on the Start of Authority （SOA） record of na.contoso.com to 15 minutes.
D.Increase the Retry Interval value on the Start of Authority （SOA） record of na.contoso.com to 15 minutes.
多项选择题 YourcompanyhasasingleActiveDirectoryforestthathassixdomains.AllDNSserversintheforestrunWindowsServer2008.YouneedtoensurethatallpublicDNSqueriesarechanneledthroughasingle-caching-onlyDNSserver.Whichtwoactionsshouldyouperform？（Eachcorrectanswerpresentspartofthesolution.（）
单项选择题 YournetworkconsistsofasingleActiveDirectorydomain.ThedomaincontainsaservernamedServer1thatrunsWindowsServer2008.AllclientcomputersrunWindowsVista.AllcomputersaremembersoftheActiveDirectorydomain.YouassigntheSecureServer（RequireSecurity）IPsecpolicytoServer1byusingaGroupPolicyobject（GPO）.UsersreportthattheyfailtoconnecttoServer1.YouneedtoensurethatuserscanconnecttoServer1.AllconnectionstoServer1mustbeencrypted.Whatshouldyoudo？（）
单项选择题 Your company has computers in multiple locations that use IPv4 and IPv6. Each location is protected by a firewall that performs symmetric NAT. You need to allow peer-to-peer communication between all locations. What should you do？ （）