When users enter their user account and credential from a client application, the server consults the appropriate user account store and validates the authenticity of the user account and the associated credential. Currently, the credential consists of a password, but vSphere also supports certificates, such as X.509 certificates. Authenticated users can then access objects they are authorized to use. Authentication succeeds if a user identity exists as a user account on the target system or in a supported directory service.

ESXi leverages standard Linux infrastructure, including the Linux pluggable authentication module (PAM) mechanism for user account creation and management. The VMware authentication daemon (vmware-authd) is implemented as a PAM module. You can create and manage user accounts on an ESXi system by using HostLocalAccountManager.