Which parameter is used in the database on a slave server to direct clients wanting to make changes to the OpenLDAP database to the master server?

The parameter used in the configuration of a slave server in OpenLDAP to direct clients wanting to make changes to the database on the master server is known as updateref. This directive is particularly important in a replicated environment, as it specifies the URL of the master server where updates should be directed.

When a client attempts to perform operations like add, modify, delete, or any other updates on a read-only replica (the slave server), it cannot process those requests as it only serves read operations. By specifying updateref, the server informs the client where it can send these update requests, effectively guiding them to the appropriate master server for the action they wish to take.

In contrast, other parameters such as updatedn and updateuri serve different purposes in the context of OpenLDAP. While updatedn defines the distinguished name that is used for updates (essentially a user that has permissions to modify the directory), updateuri is not a standard parameter in OpenLDAP configurations. This makes updateref the correct choice for routing client updates in a multi-server setup, ensuring that the architecture of the directory service remains consistent and functional.