Active Directory naming contexts
Active Directory naming contexts (NC) define boundaries for holding specific types of AD information. Each naming context partition has its own permissions structure, replication configuration, and other properties. Active Directory has three default naming contexts: Configuration, Domain, and Schema. The following sections briefly describe the three naming contexts and how Exchange 2000 Server uses them.
Configuration naming context
The configuration naming context contains Exchange information such as address list services, addressing templates, display templates, administrative groups, routing groups, connections to other Exchange servers, recipient policies, instant messaging settings, message delivery settings, and Internet message formats. Exchange servers use the configuration naming context to hold most of the Exchange-specific information. Since the configuration naming context is common to all domain controllers within the forest, Exchange servers can query a local domain controller to get this type of information.
Domain naming context
The domain naming context defines the boundaries of the Windows 2000 domain and contains all objects for the domain. The domain NC is unique to each domain within a forest, and this information is replicated only to other domain controllers within the same domain. The domain naming context contains Exchange information such as mailboxes, mail-enabled users, groups, contacts, and public folder definitions.
Schema naming context
The schema naming context contains the class definitions for objects within the Active Directory. The class definitions are the rules that define the attributes that must be included with each specific type of object, the attributes that may be included with each object, and the place within the Active Directory hierarchy that each type of object may be created. When Windows 2000 is installed, a default schema is created that defines all object classes needed by Windows 2000. The schema is extended during the Exchange 2000 installation to add object classes and attributes needed by Exchange.
ACTIVE DIRECTORY REPLICATION
Exchange information about users and resources must be replicated throughout the Exchange organization so that accurate information is available to every Exchange server and every Outlook user. Replication of the resource information is necessary for proper functioning of the Exchange infrastructure and replication of the recipient names ensures that messages will be delivered to the correct mailboxes.
Directory replication has changed between Exchange 5.5 and Exchange 2000. The most obvious change is that Exchange no longer has a directory and is no longer responsible for replicating directory information. Windows 2000 has assumed that responsibility. The type of information that was previously stored in the Exchange 5.5 directory is now stored in the Windows 2000 Active Directory.
Exchange 5.5 supported object-level directory replication. In Exchange 5.5, if you make changes to any attribute of a directory object, all attributes for the object — not just the changed attribute — were replicated to other Exchange servers. For example, if you changed the telephone number for a particular user, the user’s telephone number, display name, address, city, state, e-mail addresses and all other attributes for the user object were replicated to other servers. With object-level replication, even minor changes to selected object attributes within the directory could cause significant net-work traffic.
Windows 2000 (and thus Exchange 2000) uses a per-attribute replication mechanism. If you make changes to any attribute of a directory object, only the changed attribute is replicated. Using the same example as before, if you change a user’s telephone number, only the modified telephone number is replicated — not the entire user object. Per-attribute replication is more efficient and generates less network traffic than with Exchange 5.5.
By default, objects within the domain naming context, such as user objects, are only replicated between domain controllers within the local domain. Selected object attributes from the domain naming context are tagged for replication to the Global Catalog. The Global Catalog is replicated to all Global Catalog servers within the Windows 2000 forest. This allows processes and users in all domains to access selected attributes that normally would not be replicated outside of the local domain. Table 2 includes some of the user attributes that are included by default in the Global Catalog. You will notice that not all user attributes are tagged for replication to the Global Catalog. You can mark additional attributes for Global Catalog replication using the Schema Manager MMC console.
The per-attribute replication mechanism and the use of the Global Catalog have some benefits for Exchange. They also affect some of the ways you may be currently managing your Exchange environment. Users, contacts, and groups are now objects that exist in the Active Directory rather than in a separate Exchange directory. The per-attribute replication means that you can make more frequent changes to object attributes without significantly increasing network traffic.
Synchronizing directory data between forests
A single Exchange 2000 organization cannot span multiple forests. If you have multiple forests, then you must have multiple Exchange 2000 implementations. It is best to avoid this situation, but it is not always possible. There are several legitimate business reasons that may force you to support multiple Exchange implementations for multiple forests. The most obvious reason is when two companies merge, and they had both already implemented their own separate Windows 2000 forests. There are also situations where different divisions of the same company are legally required to maintain separate environments.
Unless you have an overwhelming business reason for implementing multiple forests, you should avoid doing so. Once you implement multiple forests, there are no automated tools for merging them.
If you find yourself unavoidably faced with multiple forests, you can create manual trust relationships between specific domains in the different forests. However, these are nontransitive trusts, which means you will have a domain model that resembles a Windows NT 4.0 environment, with multiple manual trusts between each domain.
You will also need to replicate data between the two separate Exchange implementations. Since the standard Windows 2000 replication process cannot span multiple forests, this replication must be done using other mechanisms. Several options are available for synchronizing multiple forests. Compaq’s LDAP Synchronization Utility (LDSU) and other third-party tools can be used for this purpose. (See http://www.compaq.com/ser-vices/message/mc_ldsu.html for additional information about LDSU.)
A Public Folder Inter-organization Replication tool is included with Exchange 2000. This tool can synchronize public folders between different Exchange organizations. The Public Folder Inter-organization Replication tool can also replicate Free/Busy System folders, thus allowing users from different forests to schedule meetings with one another and look up free and busy time-slots.
MANAGING A MIXED ENVIRONMENT USING THE ACTIVE DIRECTORY CONNECTOR
Before upgrading to Exchange 2000, you must first upgrade the underlying operating system to Windows 2000. As you upgrade to Exchange 2000, it may be difficult to upgrade all Exchange servers at the same time. During this migration period, you will have a mixed environment consisting of Windows 2000, Exchange 5.5, and Exchange 2000. During this coexistence period you will have two directories — the Exchange 5.5 directory and the Windows 2000 Active Directory. Keeping separate directories synchronized is a difficult problem. Thankfully, the Active Directory Connector (ADC) is available to ease the administrative difficulties.
The Active Directory Connector (ADC) is a service that synchronizes the Windows 2000 Active Directory with the Exchange Server 5.5 directory. This synchronization can be used to help populate the Active Directory for companies that have an existing Exchange Server 5.5 implementation. Synchronizing the Exchange Server 5.5 and Windows 2000 directories is also necessary for maintaining a mixed environment containing both Exchange Server 5.5 and Exchange 2000. Since the Windows 2000 Active Directory is the Global Address List for Exchange 2000 users, it is important for all mail objects to be listed in the Active Directory.
The Active Directory Connector is not automatically installed when you install Windows 2000 or Exchange 2000; it is installed as an optional component. When you install ADC, the installation process adds a new Windows 2000 service identified as MSADC and a new Microsoft Management Console snap-in for managing configuration agreements (CAs) between the Exchange 5.5 and Windows 2000 directories. The ADC allows you to administer the directory from either Active Directory or the Exchange 5.5 directory service.
A version of the Active Directory Connector is shipped with Windows 2000. This version of the ADC includes the basic replication functionality, allowing you to replicate objects between Exchange 5.5 site naming context objects such as the recipient containers and the Active Directory. If you have already implemented an Exchange 5.5 environment, the basic Windows 2000 ADC can be used to quickly import much of the existing Exchange 5.5 directory information into the Active Directory. This allows you to populate your Active Directory very quickly.
An enhanced version of the Active Directory Connector is included as an optional component with Exchange 2000 Server. You can easily install this enhanced version when you install Exchange 2000. The enhanced Exchange 2000 Server Active Directory Connector includes all of the support found in the basic Windows 2000 ADC (i.e., replication of the Exchange 5.5 site naming context), plus support for replicating the Windows 2000 configuration naming context and for downstream routing. This is needed for supporting Exchange environments that include a mixture of Exchange 5.5 and Exchange 2000 servers.
Connection agreements (CA)
When you install the Active Directory Connector, you define a Windows 2000 service. However, installing the ADC does not establish or control connections between the Windows 2000 Active Directory and any Exchange Server 5.5 directories. You establish these connections by configuring connection agreements (CAs). Each connection agreement defines and controls a relationship between an Active Directory domain and an Exchange site, and contains replication information, such as the server names, object classes to replicate, target containers, and schedule.
The Active Directory Connector and configuration agreements can be quite flexible. You can perform replication from Exchange 5.5 to Windows 2000, from Windows 2000 to Exchange 5.5, or both directions simultaneously. A single Active Directory Connector can support multiple CAs, each of which can define the relationship between different Windows 2000 Active Directory domain controllers and one or more Exchange Server 5.5 site recipient containers. There are few guidelines for configuring the connection agreements and Active Directory Connectors.
If you want to centrally manage both Windows 2000 and Exchange 5.5 objects, you must configure the connection agreement for two-way replication to every Exchange 5.5 site. This type of connection agreement supports reads and writes to both the Active Directory and the Exchange 5.5 directory.
Each Active Directory Connector can support multiple Connection Agreements. There is no theoretical limit to the number of CAs supported by each ADC, but the practical limit is that each ADC should support no more than 50 to 75 Connection Agreements. If your encounter performance problems with an Active Directory Connector, remember that it is possible to deploy multiple ADC servers to improve performance.
One obvious use for the Active Directory Connector is to perform a one-way import of Exchange 5.5 accounts into the Windows 2000 Active Directory. This provides a quick, automated method to populate the Active Directory. You can do this by configuring a one-way connection agreement in which the Exchange 5.5 mailboxes are replicated to the Active Directory. The connection agreement would be between the Active Directory and any of the Exchange 5.5 sites. Because all Exchange 5.5 information can be found on any Exchange server in the organization, all of the Exchange 5.5 objects and sites can be copied from a single connection. You do not need CAs to each of the Exchange 5.5 sites for this type of one-way replication. When changes are made to the Exchange 5.5 directory, these will automatically be replicated to the Active Directory.
Each Connection Agreement defines and controls replication between specific Active Directory organizational units and Exchange 5.5 recipient containers. One or more Exchange recipient containers can be replicated to one or more Active Directory organizational units. Multiple Connection Agreements can be used to replicate different object types between an Active Directory and a single Exchange site.
Configuration connection agreements
(ConfigCA) and site replication service (SRS)
During your migration from Exchange 5.5 to Exchange 2000, you may have a situation where an Exchange 2000 server belongs to an Exchange 5.5 site. It is important that configuration information be replicated between the Exchange 5.5 directory and the Active Directory used by the Exchange 2000 system. Replicating the configuration information ensures that the Exchange 2000 server will be represented in the Exchange 5.5 server list. This is a prerequisite for users to continue to send and receive messages regardless of which version of Exchange they happen to be using. Replicating the configuration information will also ensure that the Exchange 2000 servers will be able to send messages to connectors running on Exchange 5.5 servers and that Exchange 5.5 servers will be able to send messages to connectors running on Exchange 2000 servers.
Exchange configuration information is replicated through a special type of Connection Agreement known as a Configuration Connection Agreement (ConfigCA). The Exchange server automatically configures configuration Connection Agreements. You do not need to manually configure a ConfigCA. The first ConfigCA for an Exchange 5.5 organization is named Master_ConfigCA_orgname. The ConfigCA cannot be modified even though it can be seen using the Active Directory Connector MMC console. After replication, your Exchange 5.5 sites are listed in the Active Directory as administrative groups. If you view the Exchange 5.5 organization using the Exchange 5.5 Admin program, the Exchange 2000 servers are listed as members of the Exchange 5.5 site.
The Configuration Connection Agreement for replicating configuration information is between the Active Directory and the Exchange 2000 Site Replication Service (SRS). The Exchange 2000 Server automatically installs the Site Replication Service component when an Exchange 2000 server is installed into an Exchange 5.5 site. The SRS is similar to the Exchange 5.5 Directory Service and is used for intra-site directory replication using Remote Procedure Calls (RPCs). It uses Exchange 5.5-style LDAP calls and listens on port 379. If you upgrade an Exchange 5.5 bridgehead server to Exchange 2000, the Site Replication Service will also provide mail-based directory replication to other Exchange 5.5 sites.
Installing Active Directory connector
The Active Directory Connector can impose a heavy processing load on the host hardware system. The load placed on the ADC server’s CPU during replication is about 50 percent. The location and size of the system depends upon the size of the Exchange organization, the number of Windows 2000 domains, and the replication schedule between the two environments. Because the ADC needs to access the Active Directory, you should consider installing the ADC on a Global Catalog server. If the Global Catalog server does not have sufficient power to support the Active Directory Connector service, a good second choice is a server that has a reliable, high-bandwidth network connection to the Global Catalog server. The Exchange 5.5 bridge-head server should be on the same network segment if possible.
The Active Directory Connector software is not installed automatically when you install Exchange 2000. The following procedure can be used to install the Active Directory Connector software:
Insert the Exchange 2000 Server CD-ROM into your CD-ROM drive.
Select Run from the Windows 2000 Start menu. Enter x:\adc\i386\setup.exe, where x is your CD-ROM drive. Select OK to start the setup program.
Select Next to display the Component Selection screen ( Figure 12).
Select the Microsoft Active Directory Connector Service component check box and the Microsoft Active Directory Connector Management components check box. Select Next to continue.
Select a folder where you want the software to be installed. Select Next to continue.
Enter the account name and password under which the Active Directory Connector service will be run. When you select Next, the Active Directory Connector installation wizard begins to install the ADC software. This may take several minutes to complete.
The ADC installation wizard will display a completion message when the installation has completed. Select Finish to exit the ADC installation wizard.
You can start the Active Directory Connector service from a command prompt by typing net start msadc.
Configuring default Active Directory Connector replication policy
The Active Directory Connector and associated Connection Agreements use a variety of counters and attributes to determine which objects and attributes need to be replicated between the two environments. These counters and attributes include Connection Agreement Update Sequence Numbers (USNs), DSA-Signature attributes on Active Directory and Exchange 5.5 directory objects, Object-Version attributes, and Replicated-Object-Version attributes.
While the Exchange 5.5 directory performs object-based replication, the Active Directory does attribute-based replication. The Connection Agreement uses a combination of Active Directory USNs and the sum of Attribute Versions of each AD object in the source container to determine which Active Directory changes need to be replicated to the Exchange environment.
Figure 13 shows the mapping between some of the common Exchange 5.5 objects and Active Directory objects.
The default replication for each Connection Agreement is defined as a part of the Active Directory Connector. You can change the default attributes that will be replicated and you can also customize object matching rules. These policy settings are shared across multiple Connection Agreements associated with the ADC.
You can use the following procedure to change the attributes to be replicated for all Connection Agreements.
Select Start, Programs, Microsoft Exchange, Active Directory Connector.
Right-click Active Directory Connector Management and then select Properties.
Select From Exchange to change the attributes that will be replicated from Exchange 5.5 to Windows 2000 ( Figure 14). By default, all attributes are selected for replication. However, there may be business or technical reasons for not wanting all attributes replicated between the two environments. Attributes you select affect all Connection Agreements. If you clear an attribute on the From Exchange tab, be sure to clear the same attribute on the From Windows tab.
You can also customize the object matching rules used during replication. By default, objects are matched by GUID, legacyExchange DN, and Primary Windows NT Account. If no match is found, or if these objects are unavailable, the replication creates a new object in the directory. Select Add to create a new object matching rule. If you have any two-way Connection Agreements, you must enter the object matching criteria in both the From Exchange and From Windows tabs. This ensures that the Active Directory Connector will replicate to the same object in both locations.
Select From Windows to change the attributes that will be replicated from Windows 2000 to Exchange 5.5 ( Figure 15). By default, all attributes are selected for replication. Attributes you select affect all Connection Agreements. If you clear an attribute on the From Windows tab, be sure to clear the same attribute on the From Exchange tab.
Select Add to create a new object matching rule. If you have any two-way Connection Agreements, you must enter the object matching criteria in both the From Exchange and From Windows tabs.
Creating a connection agreement
Installing the Active Directory Connector only defines a Windows 2000 service; it does not establish or control connections between the Windows 2000 Active Directory and any Exchange Server 5.5 directories. You establish these connections by using the Active Directory Connector MMC console to configure connection agreements. You can use the following procedure to create a connection agreement:
Start the Active Directory Connector MMC console from the Windows 2000 Start menu by selecting Programs, Microsoft Exchange, Active Directory Connector.
Select Active Directory Connector Management, then right-click on the Active Directory Connector for which you wish to add a Connection Agreement and select New, Recipient Connection Agreement to display the Connection Agreement properties.
The following steps describe each of the tabs for the Connection Agreement properties. Select each tab, enter the appropriate information, and then select OK to create the Connection Agreement.
Select the General tab to display general properties for the Connection Agreement ( Figure 16).
In the Name field, enter a name for the new Connection Agreement.
Select the direction for replication. The available options are:
Two-way. Active Directory objects will be replicated to the Exchange 5.5 directory, and Exchange 5.5 objects will be replicated to the Windows 2000 Active Directory.
From Exchange to Windows. Exchange 5.5 objects will be replicated to the Active Directory, but Active Directory objects will not be replicated to the Exchange directory.
From Windows to Exchange. Active Directory objects will be replicated to the Exchange 5.5 directory, but Exchange objects will not be replicated to the Active Directory.
When you select either a two-way Connection Agreement or a one-way CA to Exchange, the Connection Agreement will modify and add attributes to each Exchange directory object it replicates. Within the Exchange environment, those modified objects will need to be replicated to all Exchange sites. The ADC replication and Exchange site replication can require considerable network bandwidth since Exchange replicates the entire object rather than just the modified object attributes. As a rule of thumb, each modified Exchange directory object will result in approximately 5 KB of replication network traffic to other Exchange servers within the site, and approximately 1 KB of network traffic to other sites. (The inter-site network traffic is less due to compression of the data.)
Use the Select a server to run the Connection Agreement drop-down list to select the Windows 2000 server where the Active Directory Connector and associated Connection Agreement will be run.
Select the Connections tab to display connection properties for the Connection Agreement ( Figure 17).
Enter values for the Windows Server information fields.
In the Server field, enter the Windows 2000 server to be used for the connection. If the ADC is installed on a member server, specify the local Global Catalog as the Windows 2000 server.
Use the Authentication drop-down list to select the type of authentication that will be used by the Windows 2000 server. Authentication is the process by which administrators who claim to have accounts on your system are verified for access. The available options are: Basic (Clear Text) using SSL. This sends clear text through a Secure Sockets Layer (SSL) encrypted channel. Using SSL encryption ensures that the entire transaction session is encrypted. Windows Challenge/Response. This type of password authentication uses the basic Windows network security. Windows Challenge/Response using SSL. This uses Windows network security through an SSL-encrypted channel. Using SSL encryption ensures that the entire transaction session is encrypted.
You should always use SSL encryption if you are replicating to a server located outside of your organization.
In the Connect As field, enter the logon credentials for connecting to the Windows 2000 server. Select Modify to select the account and enter the associated password.
Enter values for the Exchange Server information fields:
In the Server field, enter the Exchange 5.5 server to be used for the connection.
By default, the Port field is set to 389. If you have changed the default on the Exchange 5.5 server, you will need to enter the appropriate Lightweight Directory Access Protocol (LDAP) port in this field. You can determine the Exchange 5.5 port, by using the Exchange 5.5 Administrator program to examine the Protocols container.
Use the Authentication drop-down list to select the type of authentication that will be used by the Exchange 5.5 server.
In the Connect As field, enter the logon credentials for connecting to the Exchange 5.5 server. Select Modify to select the account and enter the associated password.
Select the Schedule tab to display the schedule for the Connection Agreement ( Figure 18).
Select the activation schedule for directory replication using the following options:
Use the Never button to disable directory replication.
You use the Always button to request that directory replication should happen every 5 minutes, 24 hours per day, and 7 days per week.
If you select the Selected times button, you must select the times using the daily schedule grid. During the hours you select, the Connection Agreement will check for changes every 5 minutes.
Use the Replicate the entire directory the next time the agreement is run check box to force all directory objects to be checked for consistency. Inconsistent objects will be replicated. This check box modifies the msExchServerXHighestUSN and msExchDoFull-Replication Connection Agreement attributes.
Select the From Exchange tab to display the Connection Agreement properties for Exchange recipient containers ( Figure 19). The settings on this tab are used to specify the Exchange 5.5 containers from which information will be replicated.
Select Add to add an Exchange 5.5 recipient container. To replicate all containers in the site, select the site object as the source. The Active Directory Connector will automatically create the appropriate Active Directory organizational unit hierarchy.
If a Connection Agreement is configured to write to the Exchange 5.5 directory, then the CA can only include containers from one Exchange site. If you have multiple Exchange 5.5 sites, you must create multiple Connection Agreements.
Select Modify to change the default Active Directory organizational unit where unmatched Exchange 5.5 objects will be stored in the Active Directory.
You can use the check boxes to specify the Exchange object types to replicate. The available choices are: mailboxes, custom recipients, and distribution lists.
>
Select the From Windows tab to display the Connection Agreement properties for Windows 2000 recipient containers ( Figure 20). The settings on this tab are used to specify the Active Directory organization units from which information will be replicated.
Select Add to add an Active Directory organizational unit. You need not individually select each Active Directory organizational unit. Instead, you can select the top-level domain as the source if you want to retain the same hierarchy when the organizational units are replicated to Exchange. The Active Directory Connector will automatically create all containers in the hierarchy.
Select Modify to change the default Exchange 5.5 container where unmatched Active Directory objects will be stored in the Exchange 5.5 site. Under most circumstances Active Directory user objects are mapped to a corresponding mailbox object in the Exchange 5.5 recipients container. However, if the Active Directory object does not relate to an Exchange object, then the Active Directory Connector creates an object in the default Exchange 5.5 container.
You can use the check boxes to specify the Active Directory object classes to replicate.
Select the Deletion tab ( Figure 21). The options on this tab are used to specify the actions to be taken when directory objects are removed from source and target directories.
Select the action to be taken when replicating deletions from the Windows 2000 Active Directory.
Select Delete the Exchange mailboxes, custom recipients and distribution lists to automatically delete the Exchange 5.5 objects that correspond to deleted Active Directory objects.
Select Keep the Exchange deleted items and store the deletion list in the temporary CSV file to create a list of deleted items rather than deleting the items. The list of items deleted from the Windows 2000 Active Directory is stored on the Active Directory Connector server in the following file:
\windir\MSADC\CAname\Ex55.csv
where windir is the name of the Windows directory, and CAname is the name of the Connection Agreement. By default, objects deleted from the Active Directory are not deleted from the Exchange directory.
Select the action to be taken when replicating delections from the Exchange 5.5 directory.
Select Delete the Windows disabled user accounts, contacts and groups to automatically delete the Active Directory objects that correspond to deleted Exchange 5.5 objects.
Select Keep the Windows deleted items and store the deletion list in the temporary LDF file to create a list of deleted items rather than deleting the items. The list of items deleted from the Exchange 5.5 directory is stored on the Active Directory Connector server in the following file:
\windir\MSADC\CAname\Win2000.ldf
where windir is the name of the Windows directory, and CAname is the name of the Connection Agreement. By default, objects deleted from the Exchange directory are not deleted from the Active Directory.
Enter values for the Windows Server entries per page and the Exchange Server entries per page. This is the LDAP page size. The default of 20 entries per paged result is usually adequate.
When you have multiple Exchange 5.5 sites and require two-way replication, you must have a Connection Agreement for each Exchange site. However, if each of these CAs were connected to the same Active Directory organizational unit, then the same objects would be replicated to each Exchange site. This could result in duplicate Global Address List entries since Exchange 5.5 replicates its own directory information among the sites in the Exchange organization. Clearing the This is a primary Connection Agreement for the connected Exchange Organization check box will prevent new Active Directory objects from being replicated to the Exchange site through this Connection Agreement. The CA will only replicate changes to objects that already exist in the Exchange directory.
Typically, you want only one primary CA for each Exchange organization. However, it is possible — and sometimes correct — to have multiple Connection Agreements for the same Exchange organization. Multiple CAs for the same Exchange organization are useful if the source containers or organization units differ for each Connection Agreement or if the replicated object classes are different. Also, you should have more than one primary CA if you have multiple Active Directory domains. This will allow objects other than User objects to be replicated to the Exchange directory.
From the drop-down list, select the action to be taken when replicating a mailbox whose primary Windows 2000 account does not exist in the domain. The options are:
Create a disabled Windows user account
Create a new Windows user account
From the drop-down list, select the initial replication direction for two-way Connection Agreements. The options are:
Critical Challenges of ESI & Email Retention Are you storing too much electronic information? Get expert legal advice and better understanding of what you are required to do as an IT professional.
Rev Up Your IT Know-How with Our Recharged Magazine! The improved Windows IT Pro provides trusted IT content with an enhanced new look and functionality! Get comprehensive coverage of industry topics, expert advice, and real-world solutions—PLUS access to over 10,000 articles online. Order today!
Get It All with Windows IT Pro VIP Stock your IT toolbox with every solution ever printed in Windows IT Pro and SQL Server Magazine plus bonus Web-exclusive content on hot topics. Subscribe to receive the VIP CD and a subscription to your choice of Windows IT Pro or SQL Server Magazine!
Order Your Fundamentals CD Today! Gain an introduction to Exchange, learn server security requirements, and understand how unified communications can play a role in your messaging strategies with this free Exchange CD.
Windows IT Pro
Register
