Configure single signon

With single signon (SSO) support, Web users can authenticate once when accessing Web resources across multiple WebSphere Application Servers.
Form login mechanisms for Web applications require that SSO is enabled.

SSO is supported only when Lightweight Third Party Authentication (LTPA) is the authentication mechanism.

When SSO is enabled, a cookie is created containing the LTPA token and inserted into the HTTP response. When the user accesses other Web resources in any other WebSphere Application Server process in the same domain name service (DNS) domain, the cookie is sent in the request. The LTPA token is then extracted from the cookie and validated. If the request is between different cells of WebSphere Application Servers, share the LTPA keys and the user registry between the cells for SSO to work. The realm names on each system in the SSO domain are case sensitive and must match identically.

For local OS on the iSeries (OS/400) platform, the realm name is the same as the host name.

For local OS on the Windows platform, the realm name is the domain name if a domain is in use or the machine name.

On the Linux or UNIX platforms, the release name is the same as the host name.

For the Lightweight Directory Access Protocol (LDAP) the realm name is the host:port realm name of the LDAP server. The LTPA authentication mechanism requires that you enable SSO if any of the Web applications have form login as the authentication method.

Because single signon is a subset of LTPA, it is recommended that you read Lightweight Third Party Authentication for more information. When you enable security attribute propagation, the following cookies are added to the response:

LtpaToken

The LtpaToken is used for interoperating with previous releases of WebSphere Application Server. This token contains the authentication identity attribute only.

LtpaToken2

LtpaToken2 contains stronger encryption and enables you to add multiple attributes to the token. This token contains the authentication identity and additional information such as the attributes used for contacting the original login server and the unique cache key for looking up the Subject when considering more than just the identity in determining uniqueness.

Token type	Purpose	How to specify
LtpaToken only	This token type is used for the same SSO behavior existing in WebSphere Application Server Version 5.1 and previous releases. Also, this token type is interoperable with those previous releases.	Disable the Web inbound security attribute propagation option located in the SSO configuration panel in the administrative console. To access this panel, complete the following steps: Click Security > Global security . Under Authentication, click Authentication mechanisms > LTPA . Under Additional properties, click Single signon (SSO) .
LtpaToken2 only	This token type is used for Web inbound security attribute propagation and uses the AES, CBC, PKCS5 padding encryption strength (128 bit key size). However, this token type is not interoperable with releases prior to WebSphere Application Server Version 5.1.1. The token type allows for multiple attributes specified in the token (mostly containing information to contact the original login server).	Enable the Web inbound security attribute propagation option in the SSO configuration panel within the administrative console. Disable the Interoperability mode option in the SSO configuration panel within the administrative console. To access this panel, complete the following steps: Click Security > Global security . Under Authentication, click Authentication mechanisms > LTPA . Under Additional properties, click Single signon (SSO) .
LtpaToken and LtpaToken2	These tokens together support both of the previous two options. The token types are interoperable with releases prior to WebSphere Application Server Version 5.1.1 because LtpaToken is present. The security attribute propagation function is enabled because the LtpaToken2 is present.	Enable the Web inbound security attribute propagation option in the SSO configuration panel within the administrative console. Enable the Interoperability mode option in the SSO configuration panel within the administrative console. To access this panel, complete the following steps: Click Security > Global security . Under Authentication, click Authentication mechanisms > LTPA . Under Additional properties, click Single signon (SSO) .

The following steps are required to configure SSO for the first time.

1. Access the administrative console by typing http://localhost:port_number/ibm/console in a Web browser. Port 9060 is the default port number for accessing the administrative console. During installation, however, you might have specified a different port number. Use the appropriate port number.

2. Click Security > Global security .

3. Under Authentication, click Authentication mechanisms > LTPA .

4. Under Additional properties, click Single signon (SSO) .

5. Click the Enabled option if SSO is disabled. After you click Enabled , make sure that you complete the remaining steps to enable security.

6. Click the Requires SSL option if all of the requests are expected to use HTTPS.

7. Enter the fully-qualified domain names in the Domain name field where SSO is effective. If you specify domain names, they must be fully qualified. If the domain name is not fully qualified, WebSphere Application Server does not set a domain name value for the LtpaToken cookie and SSO is valid only for the server that created the cookie.

   When you specify multiple domains, you can use the following delimiters: a semicolon (;), a space ( ), a comma (,), or a pipe (|). WebSphere Application Server searches the specified domains in order from left to right. Each domain is compared with the host name of the HTTP request until the first match is located. For example, if you specify ibm.com; austin.ibm.com and a match is found in the ibm.com domain first, WebSphere Application server does not continue to search for a match in the austin.ibm.com domain. However, if a match is not found in either the ibm.com or austin.ibm.com domains, then WebSphere Application Server does not set a domain for the LtpaToken cookie.

   You can configure the Domain name field using any of the following values:

   Domain name value type	Example
   Blank
   Single domain name	austin.ibm.com
   UseDomainFromURL	UseDomainFromURL
   Multiple domain names	austin.ibm.com;raleigh.ibm.com
   Multiple domain names and UseDomainFromURL	austin.ibm.com;raleigh.ibm.com UseDomainFromURL

   If you specify the UseDomainFromURL, WebSphere Application Server sets the SSO domain name value to the domain of the host that makes the request. For example, if an HTTP request comes from server1.raleigh.ibm.com, WebSphere Application Server sets the SSO domain name value to raleigh.ibm.com.

   Tip: The value, UseDomainFromURL, is case insensitive. You can type usedomainfromurl to use this value.

   For more information, see Single signon settings.

8. Optional: Enable the Interoperability mode option if you want to allow SSO connections in WebSphere Application Server version 5.1.1 or later to interoperate with previous versions of the application server. This option sets the old-style LtpaToken into the response so it can be sent to other servers that work only with this token type. However, this option applies only when the Web inbound security attribute propagation option is enabled. In this case, both the LtpaToken and LtpaToken2 are added to the response. Otherwise, only the LtpaToken2 is added to the response. If the Web inbound security attribute propagation option is disabled, then only the LtpaToken is added to the response.

9. Optional: Enable the Web inbound security attribute propagation option if you want information added during the login at a specific front-end server to propagate to other front-end servers. The SSO token does not contain any sensitive attributes, but does understand where the original login server exists in cases where it needs to contact that server to retrieve serialized information. It also contains the cache look up value for finding the serialized information in DynaCache, if both front-end servers are configured in the same DRS replication domain. For more information, see Security attribute propagation.

   Important: If the following statements are true, it is recommended that you disable the Web inbound security attribute propagation option for performance reasons:

   • You do not have any specific information added to the Subject during a login that cannot be obtained at a different front-end server.

   • You did not add custom attributes to the PropagationToken using WSSecurityHelper application programming interfaces (APIs).

   If you find you are missing custom information in the Subject, re-enable the Web inbound security attribute propagation option to see if the information is propagated successfully to other front-end application servers. If you disable SSO, but use a trust association interceptor instead, you might still need to enable the Web inbound security attribute propagation option if you want to retrieve the same Subject generated at different front-end servers.

10. Click OK .

What to do next

For the changes to take effect, save, stop, and restart all the product servers (deployment managers, nodes and Application Servers).

Related concepts
Web component security
Lightweight Third Party Authentication
Security attribute propagation

Related tasks
Configuring Lightweight Third Party Authentication

Related reference
Security: Resources for learning