Similar to Kerberos authentication, we can also use Lightweight Directory Access Protocol (LDAP) in MongoDB Enterprise Edition only. The user setup needs to be done in the $external database and must match the name of the authentication LDAP name. The name may need to pass through a transformation and this may cause a mismatch between the LDAP name and the user entry in the $external database.

Setting up LDAP authentication is beyond the scope of this book, but the important thing to consider is that any changes in the LDAP server may need changes in the MongoDB server, which won't happen automatically.