RE: http://docs.mongodb.org/v2.6/tutorial/configure-fips/

I don't know the full list of "out of the box" FIPS supported OSes, though apparently we only certify for some and some others are known to have issues.

For example, Ubuntu has no official FIPS module support for the OpenSSL distros: https://bugs.launchpad.net/ubuntu/+source/openssl/+bug/95001

It would be good to capture what we know of this situation in the docs rather than let customers get caught out only after they try to enable FIPS mode.