Pretty much this. Also US Govt and especially the millitary. When they buy &quot;Linux&quot; they buy RHEL. (Sometimes SUSE when they are working with Lockheed). Mostly because of support and RHEL5 and RHEL6 are certified with an alphabet soup of certifications (EAL4, FIPS-140-2, etc) and so that is what is used. Heck even RHEL7 doesn&#x27;t have all those rubber stamp even though it is 2 years old almost now.