These are some recommendation for cust getting replies from loop address 127.0.53.53   After the latest upgrades on windows system multiple customer facing problems reaching a variety or Windows* systems (PC and/or servers) thought domain names. I made a deeper investigation where I found  the ICANN announced the approval of the Name Collision Occurrence Management Framework (https://www.icann.org/en/system/files/files/name-collision-framework-30jul14-en.pdf), basically A name collision occurs when a user unknowingly accesses a name that has been delegated in the public DNS when the user's intent is to access a resource identified by the same name in a private network. Circumstances like these,  where the administrative boundaries of private and public namespaces overlap and name resolution yields unintended results, present concerns and should be avoided if possible. (for details please check the full document in the hyper link).  A recommendation will be to investigate internal name spaces to identify whether they submit invalid TLD queries to the root (form the IT side), besides I highly recommend to share the following link to your customer: The Following link is a detail guide to mitigate this name collision identification error. https://www.icann.org/resources/pages/name-collision-2013-12-06-en Please bear in mind that cisco is providing this as an extra mile as this error is beyond cisco equipment where its actually relate it with ICANN, even though I’m positive that this documentation will address a proper  solution.   Best regards,     ... View more