Devon Warshaw, Jake Mckinnon
Original Report: Schomp, Kyle, Mark Allman, and Michael Rabinovich. “DNS resolvers considered harmful.” Proceedings of the 13th ACM Workshop on Hot Topics in Networks. ACM, 2014.
We sought to reproduce several key results from the paper “DNS Resolvers Considered Harmful”, which explored the impact of running the recursive DNS resolution process directly from the end user, rather than via a shared resolver. That paper found a significant delay between DNS responses and use of the corresponding IP address in a TCP SYN packet. Until we started exploring older browser versions, we did not find that delay to the same extent as the original paper. However, we still believe that the conclusion that using local DNS resolution without a shared resolver wouldn’t significantly impact user experience is true, but that the delay that allows local resolution to have minimal impact has shifted from being located between the DNS response and TCP SYN packet to being located between the entire TCP transaction and the time the end user actually requests the resource, due to different browser prefetching mechanisms