SSO possible with LDAP-backed web applications?

I hav开发者_StackOverflow中文版e a client who wants their wordpress and google apps user accounts accessible using SSO, ie if they log in on one app domain google.client.com they will be logged into wordpress.client.com too without extra steps.

The same LDAP directory will be used to do backend authentication for both systems. Is it possible to setup SSO for LDAP-backed webapps?

You could use Open Id to achieve SSO. Google Apps and Wordpress both integrate well with openid.

The short answer is yes. Google Apps supports SAML to address SSO integration with LDAP authentication. You can get more information on a simple SAML IdP solution from www.pingidentity.com.