危险化学品有哪几类？
管理信息系统的三大核心技术是网络技术、（）和（）
Your network consists of a single Active Directory forest. The forest contains one Active Directory domain. The domain contains eight domain controllers. The domain controllers run Windows Server 2003 Service Pack 2. You upgrade one of the domain controllers to Windows Server 2008 R2. You need to recommend an Active Directory recovery strategy that supports the recovery of deletedobjects. The solution must allow deleted objects to be recovered for up to one year after the date of deletion. What should you recommend？（） Increase the tombstone lifetime for the forest.。 Increase the interval of the garbage collection process for the forest.。 Configure daily backups of the Windows Server 2008 R2 domain controller.。 Enable shadow copies of the drive that contains the Ntds.dit file on the Windows Server 2008 R2 domain controller.。
You develop a Web application that writes data to a file on a server. You restrict access to the file to specific Windows users. The Web application runs as CONTOSO\ASPNET. You deny anonymous access to the application in IIS. You add the following XML segment in the Web.config file.You need to ensure that the application meets the following requirements:It must impersonate the user when it writes data to the file.It must run as CONTOSO\ASPNET when a user does not access the file. Which two actions should you perform? （） Use the following XML segment in the Web.config file. <identity impersonate="false"/>。 Use the following XML segment in the Web.config file. <identity impersonate="true"/>。 Use the following code segment to access the file. Dim wp As WindowsPrincipal = _CType(HttpContext.Current.User, WindowsPrincipal) Dim wi As WindowsIdentity = WindowsIdentity.GetCurrent() Dim wic As WindowsImpersonationContext = wi.Impersonate()' Access the file herewic.Undo()。 Use the following code segment to access the file. Dim wi As WindowsIdentity = WindowsIdentity.GetCurrent()Dim wic As WindowsImpersonationContext = _WindowsIdentity.Impersonate(wi.Token)' Access the file herewic.Undo()。
什么是IP子网，请简述IP子网划分的作用 。
You are creating a Windows Communication Foundation (WCF) service that accepts messages from clients when they are started. The message is defined as follows:[MessageContract] public class Agent { public string CodeName { get; set; } public string SecretHandshake { get; set; }}You have the following requirements: The CodeName property must be sent in clear text. The service must be able to verify that the property value was not changed after being sent by the client. The SecretHandshake property must not be sent in clear text and must be readable by the service.What should you do?（）
