Seeking central user management software [closed]

Solution 1:

389 Directory Server / RedHat Directory server - as LDAP database backend. Standard Netscape LDAP. Fast, secure, flexible.

FreeIPA / RedHat IPA - for Identity, Policy and Audit (requires/installs 389/RH DS too). Will use kerberos and identify services via pam names. Centralized, smart, easy, secure.

p.s. Use RHEL 6 or Fedora 17 as server