isGlobalCatalogReady False - Global Catalog - Active Directory

- August 24, 2023

In this post, I describe how to fix the issue whereby a server that has been configured to be a Global Catlog shows isGlobalCatalogReady: FALSE. You can check this in ldp.exe:

Screenshot showing isGlobalCatalogReady: FALSE

The server has been configured as a Global Catalog in NTDS Settings in Active Directory Sites and Services:

Screenshot of Global Catalog checkbox checked in NTDS Settings Properties

Cause

In my case, the server was not Global Catalog ready because of a replication issue.

There are several ways to diagnose this e.g. by running the following in a command prompt:

- dcdiag

- REPADMIN /REPLSUM

- REPADMIN /SHOWREPS

- REPADMIN /SHOWREPL

You can also look in the Directory Services event log.

The local domain controller has been selected to be a global catalog. However, the domain controller does not host a read-only replica of the following directory partition.

Screenshot of "The local domain controller has been selected to be a global catalog. However, the domain controller does not host a read-only replica of the following directory partition. "

The following error occurs when I try to replicate in Sites and Services:

The DSA operation is unable to proceed because of a DNS lookup failure.

Resolution

To resolve the issue, I configured DNS on the server I wanted to be a Global Catalog to the server I was unable to replicate with (in this case TREE-TEST-2K22).