I do not know what is the best.
Maybe you better tell us more about your environment such as:
+Liferay and zimbra are in same network enviroment or not
+who will be responsible for managing IDs
,,etc.
Let's suppose ID is managed by Liferay,
using preauth in Zimbra, I think that you can implement any type of sso, OpenID type, SAML type etc. So maybe you better tell us what type of SSO you can implement with Liferay. |