# Authentication Mechanisms in MongoDB
Authentication is the process of verifying the identity of a client. When access control, i.e. authorization, is enabled, MongoDB requires all clients to authenticate themselves in order to determine their access.
MongoDB supports a number of authentication mechanisms that clients can use to verify their identity. These mechanisms allow MongoDB to integrate into your existing authentication system.
# Authentication Mechanisms
MongoDB supports multiple authentication mechanisms.
Client and User Authentication Mechanisms
Internal Authentication Mechanisms