Single sign-on for authentication using LTPA cookies

With single sign-on (SSO) support, web users can authenticate once when accessing both WebSphere® Application Server resources, such as HTML, JavaServer Pages (JSP) files, servlets, enterprise beans, and Lotus® Domino® resources, such as documents in a Domino database, or accessing resources in multiple WebSphere Application Server domains.

Application servers distributed in multiple nodes and cells can securely communicate using the Lightweight Third Party Authentication (LTPA) protocol. LTPA is intended for distributed, multiple application server and machine environments. LTPA can support security in a distributed environment through cryptography. This support permits LTPA to encrypt, digitally sign, and securely transmit authentication-related data, and later decrypt and verify the signature.

LTPA also provides the SSO feature wherein a user is required to authenticate only once in a domain name system (DNS) domain and can access resources in other WebSphere Application Server cells without getting prompted. Web users can authenticate once to a WebSphere Application Server or to a Domino server. This authentication is accomplished by configuring WebSphere Application Servers and the Domino servers to share authentication information.

Without logging in again, web users can access other WebSphere Application Servers or Domino servers in the same DNS domain that are enabled for SSO. You can enable SSO among WebSphere Application Servers by configuring SSO for WebSphere Application Server. To enable SSO between WebSphere Application Servers and Domino servers, you must configure SSO for both WebSphere Application Server and for Domino.

Prerequisites and conditions

To take advantage of support for SSO between WebSphere Application Servers or between WebSphere Application Server and a Domino server, applications must meet the following prerequisites and conditions:
  • Verify that all servers are configured as part of the same DNS domain. The realm names on each system in the DNS domain are case sensitive and must match identically. For example, if the DNS domain is specified as mycompany.com, then SSO is effective with any Domino server or WebSphere Application Server on a host that is part of the mycompany.com domain, for example, a.mycompany.com and b.mycompany.com.
    Attention: Cross-domain SSO is not supported, for example z.AAAcompany.com and w.BBBcompany.com - where the DNS domains are different.
  • Verify that all servers share the same registry.

    [AIX Solaris HP-UX Linux Windows][IBM i]This registry can be either a supported Lightweight Directory Access Protocol (LDAP) directory server or, if SSO is configured between two WebSphere Application Servers, a stand-alone custom registry.

    Domino servers do not support stand-alone custom registries, but you can use a Domino-supported registry as a stand-alone custom registry within WebSphere Application Server.

    You can use a Domino directory that is configured for LDAP access or other LDAP directories for the registry. The LDAP directory product must have WebSphere Application Server support. Supported products include both Domino and LDAP servers, such as IBM® Tivoli® Directory Server. Regardless of the choice to use an LDAP or a stand-alone custom registry, the SSO configuration is the same. The difference is in the configuration of the registry.

  • Define all users in a single LDAP directory. Using multiple Domino directory assistance documents to access multiple directories also is not supported.
  • Enable HTTP cookies in browsers because the authentication information that is generated by the server is transported to the browser in a cookie. The cookie is used to propagate the authentication information for the user to other servers, exempting the user from entering the authentication information for every request to a different server.
  • For a Domino server:
    • Domino Release 6.5.4 for iSeries and other platforms are supported.
    • A Lotus Notes® client Release 5.0.5 or later is required for configuring the Domino server for SSO.
    • You can share authentication information across multiple Domino domains.
  • For WebSphere Application Server:
    • WebSphere Application Server Version 3.5 or later for all platforms are supported.
    • You can use any HTTP web server that is supported by WebSphere Application Server.
    • You can share authentication information across multiple product administrative domains.
    • Basic authentication (user ID and password) using the basic and form-login mechanisms is supported.
      Note: Form-login mechanisms for web applications require that SSO is enabled.
    • By default, WebSphere Application Server does a case-sensitive comparison for authorization. This comparison implies that a user who is authenticated by Domino matches the entry exactly (including the base distinguished name) in the WebSphere Application Server authorization table. If case sensitivity is not considered for the authorization, enable the Ignore Case property in the LDAP user registry settings.