few days ago, started work wso2 identity server in project authorization server in architecture, found can interfaced external data source ldap, can use enterprise ldap instead re-create users , roles in wso2 is.
question authentication on wso2 is, when user authenticates on wso2 , approves access done https protocol.
don't know if it's possible use authentication protocol kerberos or radius connect wso2 is?
by default wso2 on frontend supports oauth 2.0, saml 2.0, openid , ws-trust sts protocol. indeed based on https. next may use kerberos kdc.
for kerberos configuration may check article. http://wso2.com/library/articles/2012/07/kerberos-authentication-using-wso2-products/
g.