On this page

• Authentication Methods
• Authentication Mechanisms
• Internal Authentication
• Authentication on Sharded Clusters

Authentication Methods

To authenticate as a user, you must provide a username, password, and the authentication database associated with that user.

To authenticate using the mongo shell, either:

• Use the mongo command-line authentication options (--username, --password, and --authenticationDatabase) when connecting to the mongod or mongos instance, or

• Connect first to the mongod or mongos instance, and then run the authenticate command or the db.auth() method against the authentication database.

  Important

  Authenticating multiple times as different users does not drop the credentials of previously-authenticated users. This may lead to a connection having more permissions than intended by the user, and causes operations within a logical session to raise an error.

For examples of authenticating using a MongoDB driver, see the driver documentation .

Authentication Mechanisms

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.

MongoDB supports multiple authentication mechanisms:

• SCRAM (Default)
• MongoDB Challenge and Response (MONGODB-CR) (Deprecated as of MongoDB 3.6)
• x.509 Certificate Authentication.

In addition to supporting the aforementioned mechanisms, MongoDB Enterprise also supports the following mechanisms:

• LDAP proxy authentication, and
• Kerberos authentication.

Internal Authentication

In addition to verifying the identity of a client, MongoDB can require members of replica sets and sharded clusters to authenticate their membership to their respective replica set or sharded cluster. See Internal Authentication for more information.

Authentication on Sharded Clusters

In sharded clusters, clients generally authenticate directly to the mongos instances. However, some maintenance operations may require authenticating directly to a specific shard. For more information on authentication and sharded clusters, see Sharded Cluster Users.