Authentication

The .NET driver supports all MongoDB authentication mechanisms including those in the Enterprise Edition.

Authentication credentials are created by the application as instances of MongoCredential which includes static factory methods for each of the supported authentication mechanisms. A list of these instances must be passed to the driver using the MongoClient constructor that takes a MongoClientSettings. When only one credential is necessary, it is possible to specify via the connection string.

Default

MongoDB 3.0 changed the default authentication mechanism from MONGODB-CR to SCRAM-SHA-1. To create a credential that will authenticate properly regardless of server version, create a credential using the following static factory method.

var credential = MongoCredential.CreateCredential(databaseName, username, password);

Or via the connection string:

mongodb://username:password@myserver/databaseName

This is the recommended approach as it will make upgrading from MongoDB 2.6 to MongoDB 3.0 seamless, even after upgrading the authentication schema.

x.509 Authentication

The x.509 mechanism authenticates a user whose name is derived from the distinguished subject name of the x.509 certificate presented by the driver during SSL negotiation. This authentication method requires the use of SSL connections with certificate validation and is available in MongoDB 2.6 and newer. To create a credential of this type, use the following static factory method:

var credential = MongoCredential.CreateX509Credential(username);

Or via the connection string:

mongodb://username@myserver/?authMechanism=MONGODB-X509

Even when using the connection string to provide the credential, the certificate must still be provided via code. This certificate can be pulled out of the trust stores on the box, or from a file. However, to be used with client authentication, the X509Certificate provided to the driver must contain the PrivateKey.

var cert = new X509Certificate2("client.pfx", "mySuperSecretPassword");

var settings = new MongoClientSettings
{
    Credentials = new[] 
    {
        MongoCredential.CreateMongoX509Credential("CN=client,OU=user,O=organization,L=Some City,ST=Some State,C=Some Country")
    },
    SslSettings = new SslSettings
    {
        ClientCertificates = new[] { cert },
    },
    UseSsl = true
};

GSSAPI/Kerberos

MongoDB Enterprise supports authentication using Kerberos/GSSAPI. To create a Kerberos/GSSAPI credential, use the following method:

var credential = MongoCredential.CreateGssapiCredential(username, password);

Or via the connection string:

mongodb://username%40REALM.com:password@myserver/?authMechanism=GSSAPI

If the process owner running your application is the same as the user needing authentication, you can omit the password:

var credential = MongoCredential.CreateGssapiCredential(username);

Or via the connection string:

mongodb://username%40REALM.com@myserver/?authMechanism=GSSAPI

Depending on the kerberos setup, it may be required to specify some additional properties. These may be specified in the connection string or via code.

• CANONICALIZE_HOST_NAME

  Uses the DNS server to retrieve the fully qualified domain name (FQDN) of the host.

  credential = credential.WithMechanismProperty("CANONICALIZE_HOST_NAME", "true");
  

  Or via the connection string:

  mongodb://username@myserver/?authMechanism=GSSAPI&authMechanismProperties=CANONICALIZE_HOSTNAME:true
  

• REALM

  This is used when the user’s realm is different from the service’s realm.

  credential = credential.WithMechanismProperty("REALM", "otherrealm");
  

  Or via the connection string:

  mongodb://username%40REALM.com@myserver/?authMechanism=GSSAPI&authMechanismProperties=REALM:otherrealm
  

• SERVICE_NAME

  This is used when the service’s name is different that the default mongodb.

  credential = credential.WithMechanismProperty("SERVICE_NAME", "othername");
  

  Or via the connection string:

  mongodb://username%40REALM.com@myserver/?authMechanism=GSSAPI&authMechanismProperties=SERVICE_NAME:othername
  

In addition, it is possible to use multiple authentication mechanism properties either via code or in the connection string. In code, call WithMechanismProperty multiple times. In the connection string, separate the entries with a , (comma).

mongodb://username%40REALM.com@myserver/?authMechanism=GSSAPI&authMechanismProperties=SERVICE_NAME:othername,REALM:otherrealm

LDAP (PLAIN)

MongoDB Enterprise supports proxy authentication through a Lightweight Directory Access Protocol (LDAP) service. To create a credential of type LDAP use the following static factory method:

var credential = MongoCredential.CreatePlainCredential("$external", username, password);

Or via the connection string:

mongodb://username:password@myserver/?authSource=$external&authMechanism=PLAIN