alt Hacker NewsThe myth of DNS “propagation” needs to die. Changed DNS entries do not “propagate”. The old cached DNS entries in DNS resolvers simply expire, in an arbitrary order. DNS resolvers are not linked geographically; there is no “propagation”.
If this tool was querying a list of widely-used public (and/or private) DNS resolvers, it might be useful. But pretending that DNS entries propagate geographically does not do anyone any favors.
That's what the tool is doing - querying a bunch of public resolvers around the world to see the state of what they resolve to. Since end users usually use DNS servers close to their location, this gives an idea, around the world, of who sees what.
Agreed, this is a cache that expires and refreshes from the source DNS server. It just looks like a virus that propagates when the cache expires.