> Apart from ipa are there any other good tools out there for centralised user > auth? I am currently testing LDAP (openldap) combined with nss_ldap, configured with authconfig. It works and the nice thing is that you can have consistent authentication at OS and application level (apache, PHP, java, etc.). Combined with NFS mounted home directories, it also gives you consistent uids across the hosts. However I am still evaluating the security implications of the bind process: if the access rights are too restrictive in openldap it doesn't work. It depends if everything will run in the same LAN or if you need external access. Then you probably need to go the client certificate route + SSL/TLS, which is not trivial to deploy (but works as well). If you go this way, I can share some of my findings in more details.