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Use x.509 Certificate for Membership Authentication

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  • Member x.509 Certificate
  • Configure Replica Set/Sharded Cluster
  • Additional Information

MongoDB supports x.509 certificate authentication for use with a secure TLS/SSL connection. Sharded cluster members and replica set members can use x.509 certificates to verify their membership to the cluster or the replica set instead of using keyfiles. The membership authentication is an internal process.


Starting in version 4.0, MongoDB disables support for TLS 1.0 encryption on systems where TLS 1.1+ is available. For more details, see Disable TLS 1.0.

Enabling internal authentication also enables Role-Based Access Control. Clients must authenticate as a user in order to connect and perform operations in the deployment.


A full description of TLS/SSL, PKI (Public Key Infrastructure) certificates, in particular x.509 certificates, and Certificate Authority is beyond the scope of this document. This tutorial assumes prior knowledge of TLS/SSL as well as access to valid x.509 certificates.


You must have valid x.509 certificates.

Starting in MongoDB 4.2, if you specify --tlsAllowInvalidateCertificates or net.tls.allowInvalidCertificates: true when using x.509 authentication, an invalid certificate is only sufficient to establish a TLS connection but it is insufficient for authentication.

Use member certificates to verify membership to a sharded cluster or a replica set. Member certificates are stored in net.tls.clusterFile and net.tls.certificateKeyFile. Member certificate requirements:

  • A single Certificate Authority (CA) must issue all x.509 certificates for the members of a sharded cluster or a replica set.

  • The x.509 certificate must not be expired.


    Changed in version 4.4: mongod / mongos logs a warning on connection if the presented x.509 certificate expires within 30 days of the mongod/mongos host system time. See x.509 Certificates Nearing Expiry Trigger Warnings for more information.

  • The Distinguished Name (DN), found in the member certificate's subject, must specify a non-empty value for at least one of the following attributes:

    • the Organization (O)

    • the Organizational Unit (OU)

    • the Domain Component (DC)

  • Each cluster member certificate must have identical Os, OUs, and DCs in their net.tls.clusterFile and net.tls.certificateKeyFile certificates. This also applies to the tlsX509ClusterAuthDNOverride value, if set. Attribute order doesn't matter.

    Here's an example. The two DNs below have matching specifications for O and OU, and DC is not specified.

    C=US, ST=CA, O=MongoDB, OU=Dept1, CN=host2

    The following example is incorrect, because the DNs don't match. One DN has two OU specifications and the other has only one OU specification.

  • Either the Common Name (CN) or one of the Subject Alternative Name (SAN) entries must match the server hostname for other cluster members. Starting in MongoDB 4.2, when comparing SANs, MongoDB can compare either DNS names or IP addresses. In previous versions, MongoDB only compares DNS names.

    For example, the certificates for a cluster could have the following subjects:

    subject= CN=<myhostname1>,OU=Dept1,O=MongoDB,ST=NY,C=US
    subject= CN=<myhostname2>,OU=Dept1,O=MongoDB,ST=NY,C=US
    subject= CN=<myhostname3>,OU=Dept1,O=MongoDB,ST=NY,C=US
  • If the certificate includes the Extended Key Usage (extendedKeyUsage) setting, the value must include clientAuth ("TLS Web Client Authentication").

    extendedKeyUsage = clientAuth

Outside of rolling upgrade procedures, every component of a replica set or sharded cluster should use the same --clusterAuthMode setting to ensure it can securely connect to all other components in the deployment.

For replica set deployments, this includes all mongod members of the replica set.

For sharded cluster deployments, this includes all mongod or mongos instances.


Starting in MongoDB 3.6, mongod and mongos bind to localhost by default. If the members of your deployment are run on different hosts or if you wish remote clients to connect to your deployment, you must specify --bind_ip or net.bindIp. For more information, see Localhost Binding Compatibility Changes.


The procedures in this section use the tls settings/option. For procedures using the deprecated ssl aliases, see Use Command-line Options (ssl).

The tls settings/options provide identical functionality as the ssl options since MongoDB has always supported TLS 1.0 and later.

For more information, see Configure mongod and mongos for TLS/SSL.


The procedures in this section use the deprecated ssl settings/option. For procedures using their tls aliases (available in MongoDB 4.2+), see Use Command-line Options (tls).

The tls settings/options provide identical functionality as the ssl options since MongoDB has always supported TLS 1.0 and later.

For more information, see Configure mongod and mongos for TLS/SSL.

To upgrade from keyfile internal authentication to x.509 internal authentication, see Upgrade from Keyfile Authentication to x.509 Authentication.

To perform a rolling update of the certificates to new certificates with different DN, see Rolling Update of x.509 Cluster Certificates that Contain New DN.

←  Rotate Keys for Sharded ClustersUpgrade from Keyfile Authentication to x.509 Authentication →