Issues with testing tests (DNS randomization checks)

There are several threads about various DNS testing tools sometimes reporting ISPs have or have not "patched/changed" their DNS servers. This particular thread collects several of the issues in regards to the Comcast DNS servers, but the same issues with the testing sites is applicable to anyone testing other DNS servers. http://www.dslreports.com/forum/r20839639-DNS-Comcast-and-the-DNS-Server-fla...