User authentication is one of the key principals of Active Directory as a directory system. It is safe to say that when user authentication does not exist in an Active Directory environment, then there is no need to have an Active Directory in our organization.
A friend of mine recently had problems regarding uploading certificates to GAL. As a matter of fact the users were unable to upload certificates when they choose "Publish To GAL". In this case the most errors you get is "Microsoft office Outlook was unable to publish your certificates. The server may be offline or your certificates may be invalid".
Recently I faced a request from a client wanting a Dynamic Security Group in Active Directory which automatically update its members.. However we do have the concept of dynamic objects in Active Directory (I promise to speak on that on another article), but this one was completely different. The client wanted to have a security group which automatically removes the disabled users from it. So I started a lovely conversation with my lovely friend PowerShell.