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Configure the application server and DB2 to authenticate with Kerberos

The Kerberos authentication mechanism may be used when both WebSphere Application Server and the DB2 server are configured for Kerberos authentication. Kerberos authentication can provide single sign on (SSO) end-to-end interoperable solutions and preserves the original requester identity.

In the application server, we can configure a DB2 data source, the application server, and the application so that the DB2 data source and the application server interoperate using delegated Kerberos credentials in an end-to-end manner for database access by the application. In order to take advantage of DB2 Kerberos authentication using delegated credentials from the application server, referred to in this topic as option 1, we need to configure both DB2 and the application server to use Kerberos as the authentication mechanism. See the topic, "Kerberos (KRB5) authentication mechanism support for security" to learn how to set up Kerberos as the authentication mechanism in this version of the application server.

The XARecovery and TestConnection facilities of the application server are not able to supply delegated Kerberos credentials to the data source. There might also be situations where the application server security component is unable to supply delegated Kerberos credentials for a given connection request. To account for these cases we can configure a DB2 connection using Kerberos authentication referred to in this topic as option 2. For this option, a user ID and password must be supplied to the JDBC driver that the driver uses to obtain its own Kerberos credentials. To use this option, configure a J2C authentication data alias on the application server which defines the user ID and password that the DB2 JDBC driver will use to request a Kerberos Ticket Granting Ticket (TGT). The TGT is used for Kerberos authentication to a DB2 server. To the application server, this looks much like the typical user ID and password authentication.

We must use a DB2 JDBC driver that supports Kerberos authentication and is operating in type 4 mode. The supported JDBC drivers are:

Use the following steps to configure the application server and DB2 to authenticate with Kerberos:


Tasks

  1. Configure the DB2 Server for Kerberos authentication. Refer to DB2 Kerberos security documentation in the DB2 information center, for example, the topic "Kerberos authentication details". Another helpful reference is "DB2 UDB Security, Part 6" located on the IBM developerWorks website. Verify that DB2 Kerberos authentication is working.

  2. Configure the application server to use Kerberos security. See the topic "Configuring Kerberos as the authentication mechanism using the administrative console". Verify that application server Kerberos authentication is working.

  3. Configure the DB2 data source in the application server to use Kerberos authentication. There are two steps to complete this task, we need to configure the resource adapter in the application server to pass Kerberos credentials and password credentials to the JDBC driver and secondly, we need to configure the JDBC driver to use Kerberos authentication when connecting to the DB2 server. For more information on completing these steps, see the topic "Configuring a data source using the administrative console".

    Name Value
    kerberosServerPrincipal

    This property is optional except when connecting to a DB2 server running on a z/OS platform (as of DB2 for LUW, v8 FP11).

    		user@REALM

    or

    service_name/hostname@REALM

    SecurityMechanism

    A value for this property of 11, indicates that the JDBC driver needs to use Kerberos authentication when connecting to the DB2 server.

    		11

    1. For option 2, we should configure the "Mapping-configuration alias" to "DefaultPrincipalMapping", or another login configuration which does not generate GSSCredentials, and set the "Container-managed authentication alias" to reference an alias to use for Kerberos login by the JDBC driver. The testConnection facility also uses this alias if no component-managed authentication alias is configured.

    2. For option 1, delegated Kerberos credentials, we should configure the "Mapping-configuration alias" to "KerberosMapping". This will indicate that the resource adapter in the application server should provide delegated credentials to the DB2 JDBC driver. The testConnection facility and XA transaction recovery facility are not able to supply delegated Kerberos credentials, but can revert to option 2 authentication. If we do not need those features, we can select none for each of the authentication aliases. If testConnection is used and a valid authentication alias is configured, an informational message, DSRA8221I, is logged. This message indicates that testConnection is not able to offer Kerberos credentials. If no alias is configured, then testConnection fails with a Kerberos invalid credentials error reported by the JDBC driver.

      If KerberosMapping is configured, but the security component is unable to provide Kerberos credentials for a particular connection request, the resource adapter can be configured to revert to connection authentication using Default Principle Mapping. To configure this fallback, select an alias from the container-managed authentication alias list. To disable this fallback, select none from the container-managed authentication alias list.

  4. To enable Kerberos mapping (option 1), you also must specify container-managed authentication. To specify container-managed authentication, the application must use a resource reference to lookup the data source The resource reference must specify KerberosMapping as the login configuration. If a login configuration is specified for a resource reference, then for application access through that resource reference, the specified login configuration takes precedence over the mapping-configuration alias value specified on the data source. A container-managed authentication alias can also be specified on the resource reference.


Related:

  • Kerberos (KRB5) authentication mechanism support for security
  • Configure LDAP user registries
  • Configure Kerberos as the authentication mechanism
  • Enable security
  • Configure a JDBC provider and data source
  • WAS data source properties