The Secure Sockets Layer (SSL) provides encrypted communication and optional authentication between a Directory Server and its clients. SSL can be used over LDAP or with DSML-over-HTTP. SSL is enabled by default over LDAP, but if you are using DSML-over-HTTP, you can easily enable SSL. In addition, replication can be configured to use SSL for secure communications between servers.
Using SSL with simple authentication (bind DN and password) encrypts all data sent to and from the server. Encryption guarantees confidentiality and data integrity. Optionally, clients can use a certificate to authenticate to Directory Server or to a third-party security mechanism through the Simple Authentication and Security Layer (SASL). Certificate-based authentication uses public-key cryptography to prevent forgery and impersonation of either the client or the server.
Directory Server is capable of simultaneous SSL and non-SSL communications on separate ports. For security reasons, you can also restrict all communications to the LDAP secure port. Client authentication is also configurable. You can set client authentication to required or to allowed. This setting determines the level of security you enforce.
SSL enables support for the Start TLS extended operation that provides security on a regular LDAP connection. Clients can bind to the standard LDAP port and then use the Transport Layer Security protocol to secure the connection. The Start TLS operation allows more flexibility for clients, and can help simplify port allocation.
The encryption mechanisms provided by SSL are also used for attribute encryption. Enabling SSL allows you to configure attribute encryption on your suffixes, which protects data while it is stored in the directory. For more information, see Encrypting Attribute Values.
For additional security, you can set access control to directory contents through access control instructions (ACIs). ACIs require a specific authentication method and ensure that data can only be transmitted over a secure channel. Set the ACIs to complement your use of SSL and certificates. For more information, see Chapter 7, Directory Server Access Control.
SSL is enabled by default over LDAP, and you can easily enable SSL for DSML-over-HTTP. In addition, there are some aspects of the SSL configuration that you might want to modify, as described in the following sections.