Tuesday, 8 April 2014

Lightweight Third Party Authentication (LTPA)

Lightweight Third Party Authentication (LTPA) is an IBM WebSphere  Application Server security protocol that enables a secure single signon (SSO) environment among WebSphere Application Servers.

Set up single sign-on (SSO) between two or more instances of WebSphere Application Server so users can authenticate to all applications running on WebSphere Application Server with a single log in. SSO on WebSphere Application Server is established through Lightweight Third Party Authentication (LTPA) keys. You export the LTPA key from one instance of WebSphere Application Server then import that key into a different instance of WebSphere Application Server to establish SSO.

You must configure each of the administrative domains to use the same DNS domain, user registry (using LDAP or a custom registry), and a common set of LTPA keys

Configuring  single sign-on (SSO)  on WebSphere Application Server

1 Enabling single sign-on
2 Exporting the LTPA key
3 Importing the LTPA key
4 Verifying single sign-on

Important: Synchronize the time on each instance of WebSphere Application Server for which you plan to set up SSO. LTPA tokens use timestamps from the server to timeout. SSO failures can occur because the time difference between servers is greater than the timeout value of the LTPA tokens.

Enabling single sign-on

Enable single sign-on (SSO) on all the instances of WebSphere Application Server for which you plan to establish SSO.

To enable SSO on WebSphere Application Server, do the following:

1. Log in to the WebSphere Application Server administration console.
2. Navigate to Security > Global Security.

3. In the Authentication cache settings section, expand Web and SIP security then select Single sign-on (SSO).























4. In the General Properties section, specify the following configuration values for single sign-on:























Ø  Enabled  : Selected by default.
Ø  Requires SSL :  If you want select otherwise leave it 
Ø  Domain Name: Specify the domain name that you are using for the servers. or you can leave it
Ø  Interoperability Mode Select this field if not selected by default.
Ø  Web inbound security attribute propagation Selected by default.

5.  Click OK and save to the master configuration.


















Repeat the preceding steps for the other instances of WebSphere Application Server for which you plan to establish SSO.

Exporting the LTPA key

Export a Lightweight Third Party Authentication (LTPA) key from WebSphere Application Server to import into other instances of WebSphere Application Server. You only need to export the LTPA key from one server.

Before you begin:  Enable SSO on WebSphere Application Server.

To export the single sign-on key, do the following:

1. Log in to the WebSphere Application Server administration console.
2. Navigate to Security > Global security > Authentication > LTPA.























3.In the Cross-cell single sign-on section, specify a password for the LTPA key.















4. Enter the LTPA key name and directory to which you want to export the key in the Fully qualified key
file name field. For example, on Linux, enter /u03/local/opt/was/was70/profiles/my_key_name.
5. Click Export keys.













6. Click OK and save to the master configuration.





7. Navigate to the directory where you exported the LTPA key.
8. Copy the LTPA key to the file system where you plan to import it.

Importing the LTPA key

Import the LTPA key into WebSphere Application Server. You can import the same LTPA key into multiple servers.

Before you begin
  • Export the LTPA key.
  • Copy the LTPA key from the file system where you exported it to the file system where you plan to import it.

 To import the LTPA key, do the following:
1. Log in to the WebSphere Application Server administration console.
2. Navigate to Security > Global security > Authentication > LTPA.
3. In the Cross-cell single sign-on section, specify the password for the LTPA key.
4. Enter the directory on your file system where you copied the LTPA key in the Fully qualified key file name field.
5. Click Import keys.













6. Click OK and save to the master configuration.










7. Restart both the server you exported the LTPA key from and the server into which you imported the LTPA key. Restart the servers only after you have imported the LTPA key into all the servers for which you plan to establish SSO.

Repeat the steps in this task for all servers for which you plan to set up SSO, then restart all servers.

Verifying single sign-on

You have successfully established SSO between multiple instances of WebSphere Application Server when you can log in to one administration console then access the other administration consoles without having to log in again.

To verify SSO, do the following:

1. Log in to the WebSphere Application Server administration console where you exported the LTPA key.
2. In your browser's address bar, enter the URL for the WebSphere Application Server administration console where you imported the LTPA key.

If the WebSphere Application Server administration console opens without requiring you to log in, you have successfully set up SSO.


LTPA timeout value for forwarded credentials between servers


This value refers to how long the server credentials from another server are valid before they expire. The default value is 120 minutes. The value in the LTPA timeout value for forwarded credentials between servers field must be greater than the value in the Cache timeout field on the Authentication cache settings panel.

Admin Console> Security> Global Security> 
Under Authentication > LTPA 





















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