You are the network administrator for your company. The network consists of a single Active Directory domain with three sites named Site1， Site2， and Site3. The sites and site links are configured to use Site2 to connect Site1 and Site3. Each site contains three Windows Server 2003 domain controllers. A domaincontroller in each site is configured as a preferred bridgehead server. All user and group accounts are created in Site1. Several new users start work in Site2. When they attempt to log on to the network， the logon fails. You confirm that the user accounts are created and are visible in Site1 and Site2. You discover that the preferred IP bridgehead server in Site2 failed. You repair the server and confirm that replication is successful to Site2. You need to ensure that the failure of a single domain controller in any site will not interfere with Active Directory replication between sites. 
What are two possible ways to achieve this goal？（）

You are a network administrator for your company. The network consists of a single Active Directory domain. The company has offices in 25 cities. Each office is configured as a single site. You are responsible for one site that is configured as shown in the exhibit. （Click the Exhibit button.） An IP site link connects your site and the site at the company’s main office. The company replaces your router with a firewall device. The firewall is configured to allow HTTP， SMTP， FTP， NNTP， global catalog queries， and VPN packets to pass. You discover that replication with other sites is not occurring. You need to ensure that you can replicate with other sites. You need to achieve this goal without removing or reconfiguring the firewall. 
What should you do？ （）

You have a single Active Directory directory service domain. You have an application that adds Active Directory Schema attributes during installation. The attributes replicate as part of global catalog replication. Your user account is a member of the Domain Admins， Schema Admins， and Enterprise Admins global groups. You test the application and decide not to deploy it to production.  You need to ensure that the attributes that are added by the application are no longer available in Active Directory. 
Using the Active Directory Schema snap-in，what should you do？（）

You are the network administrator for Northwind Traders. The network consists of a single Active Directory forest that contains one root domain and one child domain. The forest also contains three separate sites， as shown in the Network Diagram exhibit. （Click the Exhibit button.） The network is not fully routed and there is no direct physical connection between Site1 and Site3. Site links are not bridged. You discover that the domain controllers for namerica.northwindtraders.com located in Site1 have additional accounts that are not on the domain controllers for namerica.northwindtraders.com located in Site3. You examine the directory service log in Event Viewer on a domain controller for namerica.northwindtraders.com. You discover the error message shown in the Error Message exhibit. （Click the Exhibit button.） You need to resolve the condition that is causing this error. 
What should you do？ （）