What Is The Difference Between Authentication And Authorization? Posted on March 13, 2009February 28, 2012in Categories CentOS, Debian / Ubuntu, FreeBSD, Linux, RedHat and Friends, Suse, Troubleshooting, Ubuntu Linux, UNIX, Windows last updated February 28, 2012 What is the difference between authentication and authorization? Why it is important to understand difference between the two? Authentication vs. Authorization — what are they and how do they differ?