Network Deployment (Distributed operating systems), v8.0 > Secure applications and their environment > Authenticate users > Select a registry or repository > Configure LDAP user registries


Locate user group memberships in a LDAP registry


Overview

Search, directly or indirectly, static, nested, and dynamic groups

Configurations for supported LDAP servers are pre-defined to use the optimal group membership mechanisms. They assume that the standard object types and schemas for that LDAP vendor are in use on the LDAP server.


Static group membership

Supported by all LDAP servers. The group object lists of users and groups. To determine membership we...

  1. Get the list of all groups
  2. Query each group in turn

This method does not scale.

Serveral LDAP servers, including AD and eDirectory, have user objects that contain information about the groups to which they belong, enabling direct group searches. This is an efficient method.


Dynamic group memberships

Some LDAP servers, including IBM Directory Server and Sun ONE Directory Server, can compute group membership from user object attributes. For example, in IBM Directory Server, you can return all group memberships, including static, dynamic, and nested, using the ibm-allGroups attribute. With the Sun ONE directory server we can use the nsRole attribute.

Generally the computation is performed entirely by the LDAP server and is invisible to WAS. This approach is not as efficient as direct groups, but it is more efficient than using static group queries.

In cases where dynamic group membership computation is frequently reflected back to the LDAP client, WAS is required to compose the dynamic query against LDAP for each group. This method does not scale.

Use direct group membership where possible. Use the relatively efficient dynamic group membership where the LDAP computes membership within a single query. Use static group membership, or client side dynamic group membership as a secondary alternative. This option only performs well on systems where the number of groups within the LDAP server is "small".


Evaluate the LDAP registry configuration


Results

While using the direct method, dynamic groups, recursive groups, and static groups can be returned as multiple values of a single attribute. For example, in IBM Directory Server all group memberships, including the static groups, dynamic groups, and nested groups, can be returned using the ibm-allGroups attribute. In Sun ONE, all roles, including managed roles, filtered roles, and nested roles, are calculated using the nsRole attribute. If an LDAP server can use the nsRole attribute, dynamic groups, nested groups, and static groups are all supported by WAS.

Some LDAP servers do not have recursive computing functionality. For example, although Microsoft Active Directory server has direct group search capability using the memberOf attribute, this attribute lists the groups beneath, which the group is directly nested only and does not contain the recursive list of nested predecessors. The Lotus Domino LDAP server only supports the indirect method to locate the group memberships for a user. We cannot obtain recursive group memberships from a Domino server directly. For LDAP servers without recursive searching capability, WAS security provides a recursive function that is enabled by clicking...

...in the Advanced LDAP user registry settings. Select this option only ifthe LDAP server does not provide recursive searches and you want a recursive search.


Related

Configure dynamic and nested group support for SunONE or iPlanet Directory Server
Configure dynamic and nested group support for IBM Tivoli Directory Server
Standalone LDAP registries
Dynamic groups and nested group support for LDAP
Use specific directory servers as the LDAP server
Configure LDAP user registries

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