This article was previously published under Q246228
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IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows Registry
The DSAccess profile is a set of configuration information that defines directory servers, naming contexts, LDAP port numbers, and so on. This information contains items such as global catalog servers, domain controllers (DCs), associated port numbers (if different from 389), and the associated number of LDAP connections.
For a given instance, DSAccess handles requests on a per-process basis (for example, POP3svc, Message Categorizer, Store). Specifying how DSAccess handles these requests determines the profile that is used for a given process. The current design of DSAccess does not support multiple profiles for each instance. Consequently, all processes use a single default profile. The future holds the possibility of multiple profiles for each instance so that each process can have a choice of profile to use.
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
With Microsoft Exchange 2000 SP2 the DSAccess profile can be configured through the Exchange System Manager. The GUI replaces the configuration through the Registry editor described in this article.
According to the products listed above you can configure the default DSAccess profile manually by using either of the two following options.
In the first case, the simple case, you can control the number of LDAP connections across the directory topology. This is a per-profile, per-process setting. However, DSAccess continues to automatically detect all global catalog servers and DCs within the topology, using the global catalog servers and DCs for User Context requests, and a single randomly chosen DC for Configuration Context requests. To set the number of LDAP connections, you must create the following registry entry the location provided:
LDAPConnections = REG_DWORD value = number of connections (default is 0x1)
AsyncLDAPConnections = REG_DWORD value = number of connections (default is 0x1)
The entry does not exist by default, although the absence indicates a default value of 1. The parameters indicate the number of LDAP connections to each directory server for a given profile. The number of LDAP connections is used in a round-robin fashion on a per-process basis. Each process has its own separate LDAP connection and depends on the thread model of the requesting service (synchronous or asynchronous).
In an alternate case, you can exercise more control by specifying specific DCs and global catalog servers for User Context requests, and port numbers for LDAP connections when communicating with a specific DC or global catalog server. This is in addition to the ability to specify the number of LDAP connections. The relevant registry entries are as follows:
For specifying DC or global catalog server host name:
PortNumber = REG_DWORD value = port number (default is 0x185 for DCs and 0xcc4 for global catalog servers)
When you use the DC or global catalog server host name parameter, it controls the DC or global catalog server that Exchange 2000 uses to search for user information. When you use the DC or global catalog server port number parameter, it controls the port number that is used when communicating with a given domain controller or global catalog.
When you specify the DC or global catalog server host name and DC or global catalog server port number, you need to make the following additional entry in the registry:
IsGC = REG_DWORD value = 0x1 for true, 0x0 for false
It is critical that the IsGC entry be available along with HostName entry so that the configured servers are used. Otherwise, they will be ignored and the default is to use all the servers in the domain.
If User Context is being obtained from a global catalog, ensure that the value for IsGC is set to 1.