Chapter 12.

Managing SASL

Red Hat Directory Server supports LDAP client authentication through the Simple Authentication and Security Layer (SASL), an alternative to TLS/SSL and a native way for some applications to share information securely.

Directory Server supports SASL authentication using the DIGEST-MD5and GSS-APImechanisms, allowing Kerberos tickets to authenticate sessions and encrypt data. This chapter describes how to use SASL with Directory Server.

SASL is a framework, meaning it sets up a system that allows different mechanisms to be used to authenticate a user to the server, depending on what mechanism is enabled in both client and server applications.

SASL can also set up a security layer for an encrypted session. Directory Server utilizes the GSS-APImechanism to encrypt data during sessions.

NOTE

SASL data encryption is not supported for client connections that use TLS/SSL.

1. Authentication Mechanisms

Directory Server support the following SASL encryption mechanisms:

EXTERNAL. The EXTERNAL authentication mechanism is utilized by services such as TLS/SSL. It can be used with public keys for strong authentication, such as client certificate-based authentication.

CRAM-MD5.CRAM-MD5is a simple challenge-response authentication method that provides no security layer. Red Hat recommends using a more secure mechanism such as

DIGEST-MD5 or GSS-API.

DIGEST-MD5.DIGEST-MD5is a mandatory authentication method for LDAPv3 servers. While it is not as strong as public key systems or Kerberos authentication methods, it is preferred over plain text passwords and does protect against plain text attacks.

Generic Security Services (GSS-API).Generic Security Services (GSS) is a security API that is the native way for UNIX-based operating systems to access and authenticate Kerberos services. GSS-APIalso supports session encryption, similar to TLS/SSL. (However, GSS-APIis not compatible with TLS/SSL; they cannot be used simultaneously.) This allows LDAP clients to authenticate with the server using Kerberos version 5 credentials (tickets) and to use network session encryption.

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HP UX Red Hat Direry Server Software manual Managing Sasl, Authentication Mechanisms