Friday, September 28, 2012

What's New in Windows Server 2012


       What’s New in Windows Server 2012?


Author,
Arun Chaudhary
MCP, MCTS, MCITP
(Exchange 2010)

About me: I am working as an Exchange Administrator & also a freelancer trainer of Exchange & other Microsoft Servers; I have 6+ years experience in Microsoft servers. I have written many articles on different – different topics & given Exchange Server training for more than 250 Indian & International clients.

Windows Server 2012 is the one more server OS from Microsoft, It’s a very power full OS with the many new functionality & improvement from the previous version of Microsoft OS.

What’s New in Windows Server 2012   ??????

Microsoft windows server 2012 has the following editions.

Windows Server 2012 editions:

Ø      Windows Server 2012 Datacenter is designed for highly virtualized private cloud environments.
Ø      Windows Server 2012 Standard is designed for physical or minimally virtualized environments.
Ø      Windows Server 2012 Essentials is ideal for small businesses that have as many as 25 users and 50 devices.
Ø      Windows Server 2012 Foundation provides a Windows Server experience for as many as 15 users.

Hardware requirements:

System Requirements for Windows Server 2012 Essentials


Hardware
Minimum Requirement
Recommended Requirement
Processor
1.4 GHz (64-bit) or faster with
multi-core
3.1 GHz (64-bit) or faster with
multi-core
Memory (RAM)
2 GB
8 GB
HDD Free Space
60 GB
160 GB with a 60 GB partition
*        Microsoft improved the entire previous server role from the Windows Server 2008, R2 OS.


New Changes in Windows Server 2012 Server Roles & Features.

These are the improvements in Server Roles & features.

  1. New Changes in AD-CS Server Role: An AD-CS Server role is the responsible for issuing & managing the PKI infrastructure of your organization.
The AD CS server role includes six role services:
  1. Certification Authority (CA)
  2. Web Enrollment
  3. Online Responder
  4. Network Device Enrollment Service
  5. Certificate Enrollment Policy Web Service
  6. Certificate Enrollment Web Service
Several new capabilities are available in the Windows Server 2012 version of AD CS. They include:
    • Integration with Server Manager
    • Deployment and management capabilities from Windows PowerShell®
    • All AD CS role services run on any Windows Server 2012 version
    • All AD CS role services can be run on Server Core
    • Support for automatic renewal of certificates for non-domain joined computers
    • Enforcement of certificate renewal with same key
    • Support for international domain names
    • Increased security enabled by default on the CA role service

New Changes in AD-DS Server Role:  AD-DS (Active Directory Domain Service) in Win Server 2012 provide more advanced features like: install the DC in on-premises & in the cloud, An AD Administrator can perform more quickly & effective tasks in AD using the graphically & using the scripts.
New Features of AD:
ü      AD DS in Windows Server 2012 allows you to deploy replica virtual domain controllers by “cloning” existing virtual domain controllers. You can promote a single virtual domain controller by using the domain controller promotion interface in Server Manager, and then rapidly deploy additional virtual domain controllers within the same domain, through cloning.
ü      AD DS deployment in Windows Server 2012 integrates all the required steps to deploy new domain controllers into a single graphical interface. It requires only one enterprise-level credential, and it can prepare the forest or domain by remotely targeting the appropriate operations master roles. The new deployment process conducts extensive prerequisite validation tests that minimize the opportunity for errors that might have otherwise blocked or slowed the installation. The AD DS installation process is built on Windows PowerShell, integrated with Server Manager, able to target multiple servers, and remotely deploy domain controllers, which results in a deployment experience that is simpler, more consistent, and less time consuming.
ü      Now clients also can be join domain offline, like Win server 2008R2, but with this new functionality. A computer can now be domain-joined over the Internet if the domain is DirectAccess enabled.
·          AD Recycle Bin also have some enhance features, like: simplifies object recovery through the inclusion of a Deleted Objects node in the Active Directory Administrative Center (ADAC)
Ø      Deleted objects can now be recovered within the graphical user interface
Ø      Reduces recovery-time by providing a discoverable, consistent view of deleted object
Requirements:
Recycle Bin requirements must be met:
Ø      Windows Server 2008 R2 forest functional level
Ø      Recycle Bin optional-feature must be enabled
Ø      Windows Server 2012 Active Directory Administrative Center
Ø      Objects requiring recovery must have been deleted within Deleted Object Lifetime (DOL)
Ø      By default, DOL is set to 180 days

New Features in AD-FS Server Role: AD RMS is the server role that provides you with management and development tools that work with industry security technologies—including encryption, certificates, and authentication—to help organizations create reliable information protection solutions.
For Windows Server 2012, AD RMS now has the following requirements for access to SQL Server.
Ø      The AD RMS installer account must have sysadmin permissions in the SQL Server installation.
Ø      The SQL Server Browser service must be running to locate available SQL instances.
Ø      Firewall exceptions should be enabled on the SQL server computer for ports that will be used by AD RMS setup. The TCP port for the SQL instance that will host the AD RMS databases should be enabled. The UDP port for the SQL Server Browser service should also be enabled. For example, the default ports are usually TCP port 1433 for the SQL Server instance and UDP port 1434 for the SQL Server Browser service.
New Features in Branch Cache: Branch Cache in Windows Server 2012 and Windows 8 provides substantial performance, manageability, scalability, and availability improvements.
Ø      Now Branch cache can support any number of office & any size, when deploy hosted cache with multiple server.
Ø      No need to create the GPO for each location to deploy the branch cache.
Ø      Clients can be configured through Group Policy as distributed cache mode clients by default, however they will search for a hosted cache server – and if one is discovered, clients automatically self-configure as hosted cache mode clients.
Ø      . BranchCache uses Windows file server’s state-of-the-art technology to divide files into small pieces and eliminate duplicates. This greatly increases the chance of finding duplicate pieces in independent files, resulting in greater bandwidth savings.
New Features in DHCP Server: DHCP provide very nice feature that called DHCP failover, using the DHCP failover feature, we can have 2 DHCP servers in same subnet or scope to release the IP address, both server replicate their lease information to each other, if one DHCP server failed, another will be become online automatically.
Now DHCP also can be managed from the powershell, like Server 2008, in PowerShell for DHCP Server includes 103 cmdlets, covering multiple aspects of DHCP server configuration and management.
New Features in DNS Server: New functionality in DNS Server for Windows Server 2012 includes the following.
Ø      DNS Security Extensions (DNSSEC) support is extended to include online signing and automated key management.
1.      Support for Active Directory-integrated DNS scenarios including DNS dynamic updates in DNSSEC signed zones.
2.      Support for updated DNSSEC standards, including NSEC3 and RSA/SHA-2.
3.      Automated trust anchor distribution through Active Directory.
4.      Automated trust anchor rollover support per RFC 5011.
5.      Updated user interface with deployment and management wizards.
6.      Validation of records signed with updated DNSSEC standards (NSEC3, RSA/SHA-2).
7.      Easy extraction of the root trust anchor.
Ø      DNS configuration and management is greatly enhanced with Windows PowerShell, including:
1.          Parity with the user interface and dnscmd.exe.
2.          DNS Server role installation/removal using Windows PowerShell.
3.          Windows PowerShell client query with DNSSEC validation results.
4.          Server configuration is enabled for computers running older operating systems.
New Features in Group Policy:
Ø      In Windows Server 2012, you can refresh Group Policy settings, including security settings that are set on a group of remote computers.
Ø      In Windows Server 2012, you can schedule gpupdate.exe to run on multiple computers from the GPMC or from a Windows PowerShell session by using the new Invoke-GPUpdate cmdlet.
Ø      Group Policy Results in Windows Server 2012 includes more information to help determine if a Group Policy setting was applied to a computer or user. If the results do not match the expected results, there is information about why this happened.
Ø      You can configure firewall port requirements to allow Group Policy remote RSoP reporting and remote Group Policy update.
Ø      The two starter GPOs make configuring Group Policy firewall port requirements easier. You can import the starter GPOs at the same time that you create a new GPO for this purpose.
Ø      Group Policy Administrative Template settings that support Internet Explorer 10 are added.
Ø      Windows Server 2012 and Windows 8 include Group Policy Preferences support for Internet Explorer 10.
New Features in Remote Desktop Services: Remote Desktop Services introduced a VDI deployment in Windows Server 2008 R2. In Windows Server 2012, Remote Desktop Services includes new ways to efficiently configure and manage your virtual desktops. Some of the enhancements include:
Ø      Unified central experience – Deploy VDI quickly, and then manage your pooled and personal virtual desktop deployments through a new unified central experience.
Ø      Automated and simple single-image management – Take advantage of automated ways to deploy and manage pooled virtual desktops with a virtual desktop template.
Ø      User personalization – Preserve user personalization settings for pooled virtual desktop deployments by using user profile disks.
Ø      Less expensive storage – Use inexpensive local storage with live migration functionality between host computers for pooled virtual desktops. Personal virtual desktops can use the less expensive SMB central storage.
Ø      In Windows Server 2012, Session Virtualization deployment in Remote Desktop Services includes new ways to efficiently configure and manage your session-based desktops.
Ø      Remote Desktop Services in Windows Server 2012 enables you to publish and manage resources, such as RemoteApp programs, session-based desktops, and virtual desktops, from a centralized console.
New Features in Hyper-V: These are the following new changes in Hyper-V.
Ø      Dynamic Memory improvements include support for configuring minimum memory, and Smart Paging, which is a memory management technique to provide a reliable restart experience for virtual machines configured with less minimum memory than startup memory.
Ø      Hyper-V module for Windows PowerShell includes more than 160 cmdlets to manage Hyper-V, virtual machines, and virtual hard disks.
Ø      Hyper-V feature enables you to replicate virtual machines between storage systems, clusters, and data centers in two sites to provide business continuity and disaster recovery.
Ø      Using resource metering you can now track and gather data about physical processor, memory, storage, and network usage by specific virtual machines.
Ø      SR-IOV feature allows you to assign a network adapter that supports single-root I/O virtualization (SR-IOV) directly to a virtual machine.
Ø      Hyper-V now supports use of SMB 3.0 file shares to provide storage for virtual machines.
Ø      Move the virtual hard disks used by a virtual machine to different physical storage while the virtual machine remains running.

New Features in WDS Service: Windows Deployment Services (WDS) is a server role that enables you to remotely deploy Windows operating systems. You can use it to set up new computers by using a network-based installation.
Ø      Windows Server 2012 can deploy images to ARM clients, which is a CPU architecture that is specially engineered for low-cost, low-power consumption devices such as tablets, cell phones, GPS units, portable game consoles, network routers, and media players.
Ø      WDS infrastructure for custom deployment: Install image filters, which are similar to the set of driver group filters.
Ø      Support for boot and install image priority to influence the ordering of these images as they appear in Boot Manager and WDS client image selection menus.
Ø      The Expected Deployment Results Wizard, which allows administrators to view deployment information such as the set of matching driver groups that would be sent to a prestaged device.
Ø      Ability to control which clients are able to boot from the PXE server.
Ø      Control over the boot parameters of PXE clients including boot program, prompt policy, and boot.wim instance.
Ø      Ability to control the WIM and VHD images that are deployed to the client.
Ø      More control over the drivers that are deployed to the client.
Ø      Control over the unattend file(s) that are used to customize the setup experience for the client.
Ø      Lower-level WDSUTIL commands that allow administrators to set custom metadata tags and values on deployment payload and prestaged devices that get matched to directly influence the deployment process.
Ø      DSclient.exe is a new standalone client that can perform Dynamic Driver Provisioning (DDP) queries, direct VHD application, and metadata queries.
Ø      Standalone server mode removes the dependency on Active Directory.
New Features of Windows PowerShell 3.0: Windows PowerShell 3.0 includes several significant features that extend its use, improve its usability, and allow you to control and manage Windows-based environments more easily and comprehensively.
Windows PowerShell 3.0 is backward-compatible. Cmdlets, providers, modules, snap-ins, scripts, functions, and profiles that were designed for Windows PowerShell 2.0 work in Windows PowerShell 3.0 without changes.

Disconnected Sessions: Beginning in Windows PowerShell 3.0, persistent user-managed sessions ("PSSessions") that you create by using the New-PSSession cmdlet are saved on the remote computer. They are no long dependent on the session in which they were created.

Windows PowerShell Web Access: Windows PowerShell® Web Access is a Windows Server 2012 feature that lets users run Windows PowerShell commands and scripts in a web-based console. Devices that use the web-based console do not require Windows PowerShell, remote management software, or browser plug-in installations. All that is required is a properly-configured Windows PowerShell Web Access gateway and a client device browser that supports JavaScript® and accepts cookies.

Scheduled Jobs: You can now schedule Windows PowerShell background jobs and manage them in Windows PowerShell and in Task Scheduler. Windows PowerShell scheduled jobs are a useful hybrid of Windows PowerShell background jobs and Task Scheduler tasks.

Module Auto-Loading and Cmdlet Discovery Improvements: The Get-Command cmdlet now gets all cmdlets and functions from all modules that are installed on the computer, even if the module is not imported into the current session

Map Network Drives: The New-PSDrive cmdlet has a new Persist parameter that creates Windows mapped network drives. Commands that use the Persist parameter are saved on the local computer and are equivalent to using Net Use or File Explorer to create mapped network drives

Simplified Syntax for Where-Object and ForEach-Object: The Where-Object and ForEach-Object cmdlets have been simplified to make them easier to use. Instead of requiring script blocks and symbols, you can now filter objects and run the commands on multiple objects by using commands that are more similar to natural language.

Windows PowerShell Remoting on Public Networks: The new SkipNetworkProfileCheck parameter of the Enable-PSRemoting and Set-WSManQuickConfig cmdlets lets you enable Windows PowerShell remoting on client versions of Windows on public networks. This configuration was not available in previous versions of Windows PowerShell.

Certificate Provider Support for Web Hosting: Beginning in Windows PowerShell 3.0, the Certificate Provider enhances its support for managing Secure Socket Layer (SSL) certificates for web hosting. The Certificate provider adds support for cmdlets and new dynamic parameters that create and delete certificate stores in the LocalMachine certificate store location, and find, move, and delete certificates.

Show-Command: The new Show-Command cmdlet lets you compose and run Windows PowerShell commands in a graphic user interface.

Unblock-File: The Unblock-File cmdlet lets you open files that were downloaded from the Internet. It unblocks Windows PowerShell script files that were downloaded from the Internet so you can run them, even when the Windows PowerShell execution policy isRemoteSigned. By default, these files are blocked to protect the computer from untrusted files

Web Cmdlets:  Windows PowerShell 3.0 include new cmdlets for searching the web and managing web services.
Ø      Invoke-WebRequest: Sends an HTTP or HTTPS request to a web service and parses the response.
Ø      Invoke-RestMethod: Sends HTTP and HTTPS requests to RESTful web services. It returns HTML documents and JSON objects.
Ø      ConvertFrom-Json: Converts a JSON-formatted string to a JSON object.
Ø      ConvertTo-Json: Converts any object to a JSON-formatted string.

New Windows PowerShell ISE Features: For Windows PowerShell 3.0, Windows PowerShell® Integrated Scripting Environment (ISE) has many new features, including Intellisense, expand-collapse, a unified Console pane, and saved-text "snippets.





First look of Exchange 2013 Preview:


                                    First look of Exchange 2013 preview:


Author,
Arun Chaudhary
MCP, MCTS, MCITP
(Exchange 2010)

About me: I am working as an Exchange Administrator & also a freelancer trainer of Exchange & other Microsoft Servers; I have 6+ years experience in Microsoft servers. I have written many articles on different – different topics & given Exchange Server training for more than 250 Indian & International clients.



Finally after a long wait for new Exchange Server Microsoft launch the first look of Exchange 2013 preview.

Microsoft announced the Preview edition of Exchange Server 2010 in 16th July 2012. Exchange 2010 has many enhanced security & performance option, which help your organization to work fast, smoothly & in safe environment. It provides you more control on your email communication, compare than previous version of Exchange Server.

There are some new features of Exchange 2013 preview, which will change your email server experience.

  1. Provide control, Online & On-premises: Exchange 2013 has ability to control your organization in online & on-premises or in the hybrid scenario.

  1. Move your Exchange organization in the cloud: Exchange 2013 provide you tools to move to the cloud on your own terms, it limit’s user disruption when you move user mailboxes & provide flexibility to the users for sharing their calendar & scheduled meetings, when they are online or on-premises.  


  1. Exchange Administration Centre: Exchange 2013 provide the powerful options, like – Data Loss Prevention (DLP) and site mailboxes, from a single & easy-to –use web based administration console. Using this you can also secure the ECP virtual directory & also can manage your public folder.

Server Roles: Microsoft make big change in Exchange 2013 architecture, now Exchange 2013 have only two server roles.

  1. Client Access Server Role: As per the previous version of Exchange server CAS also provide the functionality of connecting all the Exchange clients, like (e.g. Outlook, OWA, Active sync)  to the MBX Server. The CAS authenticates and redirects clients request on the base of their mailbox server query to their appropriate MBX. CAS also can be highly available like previous version of Exchange Server.

Changes in CAS: CAS has now few changes like:

Client Access Service: This service is responsible to connect all the client connection to their MBX Servers.
Front End Transport Service: FETS service provides the functionality of email traffic filtering, mail routing between the Exchange servers & outside the organization.


Mailbox Server Role: MBX is used to store all the user mailboxes & public folder data. MBX also can be highly available using DAG, like Exchange 2010. MBX also provide the two Hub Transport Server services.

Hub Transport Service: This is also same like previous version of Microsoft Exchange server & provide the mail routing service with in the Exchange organization and also a have a enhance feature in Exchange 2013, It provide a connectivity between the Front End Transport service & Mailbox Transport service.
Mailbox Transport Service: This service is responsible for send the emails between the Hub Transport Service & the Mailbox database.

Other Server Roles from Exchange 2007/2010

With the reduction in server roles to just two in Exchange Server 2013 you may be wondering what has happened to the remaining server roles that existed in Exchange Server 2007 and 2010:

Hub Transport server – this functionality has been divided between the Client Access server (Front End Transport service) and Mailbox server (Hub Transport and Mailbox Transport services) and is no longer a dedicated server role
Unified Messaging – this functionality has been divided between the Client Access and Mailbox server and is no longer a dedicated server role
Edge Transport – Exchange 2013 Preview does not contain an Edge Transport server role, however it will function with Exchange 2007 or 2010 Edge Transport.

Exchange Server 2013 Prerequisites:

Before we go to install the Exchange 2013 preview, we must have to understand that what OS, Service packs, Schema updates & Domain or Forest functional levels required.
There is a complete table for all the prerequisites of Exchange 2013 installation:

 Windows Server 2008 R2 SP1 prerequisites

To install the Exchange 2013 preview on the Win Server 2008 R2 SP1, you have to install the following features & software components.

To combine the MBX & CAS role:

Do the following to install the required Windows roles and features:
  1. Open Windows PowerShell.
  2. Run the following command to load the Server Manager module.
            Import-Module ServerManager




  1.  Run the following command to install the required Windows components.

Add-WindowsFeature Desktop-Experience, NET-Framework, NET-HTTP-Activation, RPC-over-HTTP-proxy, RSAT-Clustering, RSAT-Web-Server, WAS-Process-Model, Web-Asp-Net, Web-Basic-Auth, Web-Client-Auth, Web-Digest-Auth, Web-Dir-Browsing, Web-Dyn-Compression, Web-Http-Errors, Web-Http-Logging, Web-Http-Redirect, Web-Http-Tracing, Web-ISAPI-Ext, Web-ISAPI-Filter, Web-Lgcy-Mgmt-Console, Web-Metabase, Web-Mgmt-Console, Web-Mgmt-Service, Web-Net-Ext, Web-Request-Monitor, Web-Server, Web-Stat-Compression, Web-Static-Content, Web-Windows-Auth, Web-WMI


After you've installed the operating system roles and features, install the following software in the order shown:
  1. Microsoft .NET Framework 4.5 RC 
  2. Windows Management Framework 3.0 
  3. Microsoft Unified Communications Managed API 4.0, Core Runtime 64-bit 
  4. Microsoft Office 2010 Filter Pack 64 bit 
  5. Microsoft Office 2010 Filter Pack SP1 64 bit 
  6. Microsoft Knowledge Base article KB974405 (Windows Identity Foundation) 
  7. Knowledge Base article KB2619234 (Enable the Association Cookie/GUID that is used by RPC over HTTP to also be used at the RPC layer in Windows 7 and in Windows Server 2008 R2) 
  8. Knowledge Base article KB2533623 (Insecure library loading could allow remote code execution) 
Imp: Hot fix may be already installed on your server, If you have configure auto updates on you windows server.
For Exchange 2013 Preview, you must also do the following in the order shown:
  1. Uninstall Microsoft Visual C++ 11 Beta Redistributable (x64)   This task must be done after you've installed UCMA, but before you run Exchange 2013 Preview Setup. To uninstall Microsoft Visual C++ 11 Beta Redistributable (x64), do the following:
    1. Open Control Panel > Programs and Features.
    2. Select Visual C++ 11 Beta Redistributable (x64) - 11.0.50531 and then click Uninstall.
    3. In Microsoft Visual C++ 11 Beta setup, click Uninstall.
    4. When Microsoft Visual C++ 11 Beta is uninstalled, click Close.

Register ASP.NET with .NET Framework 4.5 in Internet Information Services (IIS)   This must be done after you've completed the process described earlier in “Uninstall Microsoft Visual C++ 11 Beta Redistributable (x64)”, but before you run Exchange 2013 Preview Setup. To register ASP.NET with .NET Framework 4.5 in IIS, do the following:
a. Open a Windows Command Prompt.
b. Run the following command:

%SystemDrive%\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -ir -enable

c.       Now restart the IIS service using this command.
IISReset
Imp: During the IIS service restart, all the active website, which are host on IIS server, will be stop the respond.
Windows 7 requirements:
Follow the instructions in this section to install the prerequisites on domain-joined Windows 7 64-bit computers where you want to install the Exchange management tools.
  1. Open Control Panel, and then select Programs.
  2. Click Turn Windows features on or off.
  3. Navigate to Internet Information Services > Web Management Tools > IIS 6 Management Compatibility.
  4. Select the check box for IIS 6 Management Console, and then click OK.
After you've installed the operating system features, install the following software in the order shown:
  1. Microsoft .NET Framework 4.5 
  2. Windows Management Framework 3.0 
  3. Knowledge Base article KB974405 (Windows Identity Foundation) .

Windows 2012 Server Prerequisites:

The prerequisites that are needed to install Exchange 2013 Preview on a Windows Server 2012 computer depends on which Exchange roles you want to install. Select the section that matches the roles you want to install.


Follow the instructions in this section to install the prerequisites on Windows Server 2012 computers where you want to do one of the following:
·             Install only the Mailbox server role on a computer.
·             Install both the Mailbox and Client Access server roles on the same computer.
Do the following to install the required Windows roles and features:
  1. Open Windows PowerShell.
  2. Run the following command to install the required Windows components.

Install-WindowsFeature AS-HTTP-Activation, Desktop-Experience, NET-Framework-45-Features, RPC-over-HTTP-proxy, RSAT-Clustering, Web-Mgmt-Console, WAS-Process-Model, Web-Asp-Net45, Web-Basic-Auth, Web-Client-Auth, Web-Digest-Auth, Web-Dir-Browsing, Web-Dyn-Compression, Web-Http-Errors, Web-Http-Logging, Web-Http-Redirect, Web-Http-Tracing, Web-ISAPI-Ext, Web-ISAPI-Filter, Web-Lgcy-Mgmt-Console, Web-Metabase, Web-Mgmt-Console, Web-Mgmt-Service, Web-Net-Ext45, Web-Request-Monitor, Web-Server, Web-Stat-Compression, Web-Static-Content, Web-Windows-Auth, Web-WMI, Windows-Identity-Foundation


After you've installed the operating system roles and features, install the following software in the order shown:
  1. Microsoft Unified Communications Managed API 4.0, Core Runtime 64-bit 
  2. Microsoft Office 2010 Filter Pack 64 bit 
  3. Microsoft Office 2010 Filter Pack SP1 64 bit 
For Exchange 2013 Preview, you must also uninstall Microsoft Visual C++ 11 Beta Redistributable (x64). This must be done after you've installed UCMA, but before you run Exchange 2013 Preview Setup. To uninstall Microsoft Visual C++ 11 Beta Redistributable (x64), do the following:
  1. Open Control Panel > Programs and Features.
  2. Select Visual C++ 11 Beta Redistributable (x64) - 11.0.50531 and then click Uninstall.
  3. In Microsoft Visual C++ 11 Beta setup, click Uninstall.
  4. When Microsoft Visual C++ 11 Beta is uninstalled, click Close.



After installing all the prerequisites for installing the Exchange 2013 preview, we have prepared the Active Directory. Before you start AD preparation must check the AD replication issues, if any fix it & then start the AD preparation.
     To track the progress of Active Directory replication, you can use the repadmin tool (repadmin.exe), which is installed as part of the Windows Server 2012 and Windows Server 2008 R2 Active Directory Domain Services Tools (RSAT-ADDS) feature.
 AD Preparation Tasks:
First put the media of Exchange 2013 preview.
Start-à Runà cmd
From the command prompt run the following commands.
Permission required:
  • Domain Admin Group
  • Schema Admin Group
  • Enterprise Admin Group
 Setup /PrepareSchema     or       Setup /PS

This command performs the following tasks:
·        Connects to the schema master and imports LDAP Data Interchange Format (LDIF) files to update the schema with Exchange 2013 Preview specific attributes. The LDIF files are copied to the Temp directory and then deleted after they are imported into the schema.
·        Sets the schema version (ms-Exch-Schema-Verision-Pt) to 15132.
Note the following:
·        To run this command, you must be a member of the Schema Admins group and the Enterprise Admins group.
·        You must run this command on a 64-bit computer in the same domain and in the same Active Directory site as the schema master. 
·        If you use the /DomainController parameter with this command, you must specify the domain controller that is the schema master.
·        After you run this command, you should wait for the changes to replicate across your Exchange organization before continuing to the next step. The amount of time this takes is dependent upon your Active Directory site topology.

Now run this command from the command prompt
setup /PrepareAD [/OrganizationName:<organization name>] or setup /p [/on:<organization name>]
This command performs the following tasks:
·             If the Microsoft Exchange container doesn't exist, this command creates it under CN=Services,CN=Configuration,DC=<root domain>.
·             If no Exchange organization container exists under CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=<root domain >, you must specify an organization name using the /OrganizationName parameter
Now run this command to prepare your domain
Run setup /PrepareDomain or setup /pd to prepare the local domain.
Or
Run Setup /PrepareAllDomains   to prepare the entire domain in your organization.
These commands perform the following tasks:
·             If this is a new organization, creates the Microsoft Exchange System Objects container in the root domain partition in Active Directory and sets permissions on this container for the Exchange Servers, Exchange Organization Administrators, and Authenticated Users groups. This container is used to store public folder proxy objects and Exchange-related system objects, such as the mailbox database's mailbox.
·             Sets the objectVersion property in the Microsoft Exchange System Objects container under DC=<root domain>. This objectVersion property contains the version of domain preparation. The version for Exchange 2013 Preview is 13236. 
·             Creates a domain global group in the current domain called Exchange Install Domain Servers. The command places this group in the Microsoft Exchange System Objects container. It also adds the Exchange Install Domain Servers group to the Exchange Servers USG in the root domain.
After running all these commands successfully, verify that your AD is prepared for the Exchange 2013 or not.
Do the following to verify that Active Directory has been successfully prepared:
·             In the Schema naming context, verify that the rangeUpper property on ms-Exch-Schema-Verision-Pt is set to 15132.
·             In the Configuration naming context, verify that the objectVersion property in the CN=<your organization>,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=<domain> container is set to 15448.
·             In the Default naming context, verify that the objectVersion property in the Microsoft Exchange System Objects container under DC=<root domain is set to 13236.