Solved: How do I use nested groups in a Fortinet Single-Sign-On?

This article describes how nested groups can be used in a Fortinet Single-Sign-On context.

Solution

Nested groups, in an Active Directory environment, refer to a group which is in turn a member of another group – one group is nested inside another.

This can present some challenges to group filtering, in particular the following scenario:

• User A is member of group 1.
• Group 1 is member of group 2 (nested inside group 2).
• The FSSO setup is filtering on group 2, not explicitly group 1.

The expectation might be that Collector Agent detects logins for user A, notices a membership for group 1 explicitly, and notices the indirect membership in group 2, shares this information with FortiGate, and FortiGate treats the user A as a member of group 1 and group 2, even though the user is only explicitly a member of group 1.

However, this is not automatically the case.

Collector Agent only detect nested groups in advanced mode.

The following settings are required to support nested groups in FSSO:

• On FortiGate, in the External Connector set the group filter source to Local and select groups from an LDAP server to function as group filter.
• On Collector Agent, switch it to Advanced Mode under Directory Access Information settings (this requires running the Collector Agent as administrator).