70-412: Configuring Advanced Windows

Server 2012 services

Chapter 5Configuring the Active Directory

Infrastructure

Objective 5.1: Configuring a Domain

and Forest

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Active Directory• Active Directory is a technology created by

Microsoft that provides a variety of network services, including:o Lightweight Directory Access Protocol (LDAP)o Domain Name System (DNS) based naming and other

network informationo Security mechanism for authentication that includes

Kerberos-based and single sign-on authenticationo Security mechanism for authorization and auditingo Central location for network administration and

delegation of authorityo Policy-based management for user and computer

accounts

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Logical Components of Active Directory

• Organizational unitso Containers in a domain that allow you to organize and group

resources for easier administration, including delegating administrative rights.

• Domainso An administrative boundary for users and computers, which

are stored in a common directory database. o A single domain can span multiple physical locations or sites

and contain millions of objects.

• Domain treeso Collections of domains that are grouped together in

hierarchical structures and that share a common root domain. o Can have a single domain or many domains. The domains

within a tree have a contiguous namespace.

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Logical Components of Active Directory

• Forestso Collections of domain trees that share a common AD DS directory

schema. o Can contain one or more domain trees or domains, all of which share

a common logical structure, global catalog, directory schema, and directory configuration, as well as automatic two-way transitive trust relationships.

o The first domain in the forest is called the forest root domain. o For multiple domain trees, each domain tree consists of a unique

namespace.

• Trust relationshipso Allow users in one domain to access resources in another domain. o Domains within a tree and forest are automatically created as two-

way transitive trusts. • A transitive trust is based on the following concept: If domain A

trusts domain B, and domain B trusts domain C, then domain A trusts domain C.

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Active Directory Database

• An Active Directory database is logically separated into the following directory partitions:o Schema partition (one per forest)o Configuration partition (one per forest)o Domain partition (one per domain)o Application partition

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Single Domain versus Multiple Domains

• A single domain offers centralized management, where a set of administrators manage everything within the domain.

• Although multiple domains can be centrally managed, multiple domains also offer decentralized management, where different administrators manage each domain.

• If an organization establishes a presence in a foreign country and there are political or legal reasons to have separate security domains, you might consider implementing separate domains.

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User and Resource Domains

• Some companies define user domains and resource domains: o User domains: Used to manage users.

Administrators of the user domain have full administrative control over the user accounts, and can create, manage, and remove user accounts.

o Resource domains: Sometimes managed by different management teams that help secure resources.

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Multi-Forest Active Directory

Environments• Separate Active Directory forests also offer

isolated security. • By having separate forests, each forest

root domain has the Schema Admins and Enterprise Admins AD DS forest.

• Separate forests are often deployed by government defense contractors and other organizations that require security isolation.

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Active Directory Schema

• The Active Directory schema defines the objects and attributes of those objects.

• Because the schema is shared between domains, the domain admins of the various domains must agree on the schema changes.

• Therefore, if you require different schemas, you can use multiple forests.

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Upgrading Existing Domains and Forests

• Because Active Directory is a key component for many organizations, you must maintain Active Directory and be careful when upgrading to a newer version.

• Depending on your needs, the current state of Active Directory, and the hardware that Active Directory is running on, there are several options you can use to upgrade the Active Directory environment. These options include:o In-place upgradeo Add servers running Windows Server 2012 and promote to

domain controllerso Create a new AD DS Windows Server 2012 domain and

migrate the objects to the new domain or merge the domains together

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Upgrading Domain Controllers

• To upgrade from Windows Server 2008 or Windows Server 2008 R2 Active Directory Domain Services (AD DS), you can:o Upgrade the operating system of the existing

domain controllers to Windows Server 2012 (assuming the hardware can support it)

o Introduce Windows Server 2012 servers as domain controllers, and then decommission the older domain controllers

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Clean Installation• If you have a server running an old operating

system, and you want to move to the new operating system, you can choose to perform an upgrade or perform a clean install.

• An upgrade usually consists of starting the install program and letting the new files overwrite the old files.

• Although the upgrade tends to be simple, and quicker, the clean install allows you to start fresh with no old files or configuration on the machine.

• When you want the most reliable system, it is always best to perform a clean install.

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Upgrading the Schema

• For a domain running in Windows Server 2003, Windows Server 2008, or Windows Server 2008 R2 functional level, you can install Windows Server 2012 and add the computer to the domain.

• However, before you promote a server running Windows Server 2012 to a domain controller, you must upgrade the schema.

• In previous versions of Windows, you would use the adprep.exe tool to upgrade the schema.

• While the Windows Server 2012 includes adprep32.exe, it has been deprecated.

• Instead, the Active Directory Domain Services Installation Wizard included in Server Manager incorporates the commands necessary to upgrade the AD DS forest schema.

Objective 5.2: Configuring Trusts

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Trusts• Trusts are relationships between one

Windows domain and another Windows domain or non-Microsoft Kerberos v5 realm.

• Trusts are created to allow users in one domain the ability to authenticate and then access resources on another domain, forest, or realm.

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Trust Types• Two types of trusts can exist in a forest

and domain environment: o Automatically generated at forest/domain

creationo Manually created after forest or domain

creation, these trusts connect directly to domains and forests inside or outside the existing enterprise.

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Trust Direction• One-way incoming trust direction• One-way outgoing trust direction• Two-way trust

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Trust Types

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Transitivity• Transitivity determines how far the trust relationship

authentication requests can traverse existing trust authentication paths: o Transitive

• Trust authentication follows the flow of existing trust relationships that are part of the trusted domain.

• If a transitive trust is created with an external forest, the authentication can traverse the path of the forest's existing trusts.

o Nontransitive• An explicit trust between two domains ignores any existing

trusts in the external or internal domain or forest.• The domains in the trust only trust each other and will not

traverse any existing or future trust paths of either domain.

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Trust Authentication• Trust authentication defines how explicit the

authentication and access to the trusting domain will be.

• There are three scopes of trust authentication: selective authentication, domain-wide authentication, and forest-wide authentication.

• Trust authentication is configured on external and forest trusts.

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SID Filtering• SID Filtering protects trusting domains from

malicious users. • Malicious users might attempt to inject SIDs of

an elevated user or group in the trusting domain to the sIDHistory of a user in the trusted domain.

• When SID Filtering is disabled, the malicious user can successfully inject the sIDHistory and gain privileged administrative access to resources in the trusting domain.

• It is best practice to keep SID Filtering enabled unless absolutely necessary.

Objective 5.3: Configuring Sites

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Configuring Sites• Sites are representative of the physical AD DS

domain topology and contain domain controllers, clients, and services.

• At forest creation, the default site created is called Default-First-Site-Name, which contains all domain controllers added to the domain until new sites and subnets are created.

• Sites group domain controllers together at the same physical location to allow efficient replication between one another on high-speed internal networks before sending any directory changes to remote locations or branch offices.

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Intrasite and Intersite Replication

• All domain controllers within a site replicate with one another in a process called Intrasite replication, which is the replication of compressed data that occurs across site links between domain controllers located in different sites.

• Intersite replication, through the use of Bridgehead servers, replicates directory partitions from one site's bridgehead server to another site's bridgehead server.

• Each bridgehead server then replicates the changes internal to its replica domain controllers through Intrasite replication.

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Configuring Subnets• Subnets are created to group and assign

computers within the same network subnet to a site. Subnets can be assigned only to one site and can be IPv4 or IPv6 subnets.

• At logon, domain controllers assign clients to sites based on their network address and subnet.

• When designing an AD DS site topology, make sure all IP ranges used by clients and servers are added to a subnets list and assigned to a site for optimized service access and domain controller referencing.

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Site Links• Site links define the logical replication link between

sites to perform Intersite replication, allowing for faster and optimized replication between sites based on configured costs and frequencies.

• Site links manage the logical flow of replication between physical sites.

• The DEFAULTIPSITELINK site link object is created by default at forest creation.

• When new domains and domain controllers are added to the forest, if new sites links are not manually created, they will all become members of the DEFAULTIPSITELINK site.

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Site Links• In large enterprise environments, spanning several

physical locations, replication traffic is at the mercy of the WAN links between physical locations.

• This situation can cause replication issues when there is a mix of reliable and unreliable network paths between sites.

• Physical infrastructure between sites might differ and have different requirements about when to utilize bandwidth.

• To resolve the problem of costly bandwidth and timing restrictions of physical connections, you can implement site links.

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Intersite Transport Protocols

• IP Transporto Replicates all AD DS partitions synchronously to domain

controllers in well-connected sites. o Is efficient, reliable, and the preferred method of replication

between Intersite partners.

• SMTP Transporto Is configured with the Simple Mail Transport Protocol (SMTP)o Sends replication asynchronously via e-mail messages. o Requires the implementation of Active Directory Certificate

Services (AD CS).o Replicates only the schema, configuration, and Global Catalog

partitions. Using SMTP does not replicate the domain partition. o Can be used in situations where RPC over TCP/IP is not

configured between two sites.

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Bridgehead Servers• Bridgehead servers

o Are automatically configured by AD DS. o Take the changes made during Intrasite replication

and then replicate those changes to the bridgehead server in a connected site.

• It is best practice to allow AD DS to handle the assignment of the bridgehead server tasks to specific domain controllers.

• In certain environments, you might need to manually configure a bridgehead server dedicated to the additional processing and traffic requirements.

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Bridgehead Servers

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Site Link Bridges• Site link bridging allows transitive linking

between all sites in the forest. • Bridge All Site Links is enabled by default

to permit site link bridging between all sites in the forest.

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Replication Interval• The replication interval defines how often

replication across the site link occurs. • By default, replication on site links are configured

to occur every 180 minutes and can be modified within the site link properties.

• Replication between sites might need to occur more frequently if there are constant changes to AD DS that need to be seen in branch offices immediately.

• The replication interval can be configured to allow replication every 15 minutes across site links.

Objective 5.4: Managing Active Directory and SYSVOL Replication

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Read-Only Domain Controllers

• Read-only domain controllers (RODCs)o Are used in environments where there is a

need for a domain controller in a branch office that does not have a secured physical environment.

o Are also used when there is a risk of theft, or even rarely, when there is an application requiring installation on a domain controller that users must log in to at the terminal or with terminal services.

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Read-Only Domain Controllers

• As the name "read-only domain controller" implies, its involvement with AD DS is truly read-only.

• Unidirectional replication means replication occurs in only one direction, from a writeable domain controller to the read-only domain controller.

• Implementing Filter Attribute Sets allows administrators to mark attributes as “Confidential” when being replicated to RODCs.

• Attributes marked as confidential and that are part of the Filtered Attribute Set will not be replicated to an RODC.

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Password Replication Policy

• To provide authentication of users and computers at a branch office that utilizes an RODC, the RODC must know and store the password of that user or computer.

• To prevent unwanted users from logging in to or authenticating against an RODC, only users that are members of the Allowed RODC Password Replication Group will be allowed to authenticate to the RODC.

• As an additional option, to prevent users from authenticating against the RODC, add the users or user group to the Denied RODC Password Replication Group.

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Upgrading SYSVOL Replication

• Many environments started off as an Active Directory environment running Windows Server 2003 or earlier, prior to the addition of Windows Server 2008 and Windows Server 2012.

• The replication process of recently upgraded domain’s SYSVOL folders could still be configured to use the File Replication Service (FRS).

• The SYSVOL folder on each domain controller contains a copy of logon scripts and Group Policies, and it is a repository for public access files used by domain controllers.

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Upgrading SYSVOL Replication

• To upgrade from File Replication Service (FRS) to Distributed File System Replication (DFSR), the domain functional level must be Windows Server 2008 or higher.

• This means all domain controllers in the domain must be at least Windows Server 2008 or higher.

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Upgrading SYSVOL Replication

• Each of the four Global States of an FRS to DFSR upgrade allows all domain controllers to balance and prepare for the next state:o Start (State 0): Live AD DS SYSVOL replication

between domain controllers is performed using FRS. o Prepared (State 1): Live AD DS SYSVOL replication

between domain controllers is performed using FRS. o Redirected (State 2): Live AD DS SYSVOL replication

between domain controllers is performed using DFSR. o Eliminated (State 3): All Live AD DS SYSVOL

replication between domain controllers is performed using DFSR. FRS SYSVOL replication is removed, including the SYSVOL folder and its contents.