Subject: [Din] Evaluating Public DNS Services in the Wake of Increasing Centralization of DNS

From: Dirk Kutscher <[email-masked]>
Date: Fri, 21 May 2021 10:20:04 +0200

Trinh Viet Doan, Justus Fries, Vaibhav Bajpai published an IFIP-2021 
paper on "Evaluating Public DNS Services in the Wake of Increasing 
Centralization of DNS" that could be of interest here:

Recent studies have shown centralization in the Do- main Name System 
(DNS) around public DNS services, which are hosted on centrally managed 
infrastructure and advertise higher reliability, improved security, and 
faster response times for name resolutions. However, many of the 
recently emerged public DNS services have not yet been extensively 
studied regarding popularity and performance. In light of this, we use 
10.6k RIPE Atlas probes and find that 28.3% of the probes (and the their 
host network by extension) use at least one public DNS service, with 
Google being the most popular public DNS service among these probes. We 
further quantify the response time benefits of such public DNS services 
using ≈2.5k RIPE Atlas probes deployed in home networks (1k of which 
are IPv6 capable): Overall, we provision around 12.7M DNS requests based 
on a set of 23 domains and ten centralized public DNS services both over 
IPv4 and IPv6. For comparison, we additionally resolve the same set of 
domains using the probes’ local resolvers, which are typically managed 
by the ISP. We observe that even though IP and AS paths to local 
resolvers are generally shorter, some public DNS services (e.g., 
Cloudflare), achieve faster responses over both IPv4 and IPv6. Across 
all continents, Cloudflare, Google, and OpenDNS exhibit the lowest 
response times out of all public resolvers for successful DNS 
measurements. However, probes in Europe (EU) and North America (NA) 
experience comparable latencies to public and local resolvers, thereby 
diminishing latency benefits of public DNS services. We also observe 
inflated path lengths to and response times (over both address families) 
from most public resolvers for probes in Africa (AF) and South America 
(SA). Based on our observations, we provide recommendations and discuss 
situations in which switching to public DNS services may be beneficial.

https://vaibhavbajpai.com/documents/papers/proceedings/dns-networking-2021.pdf

Best regards,
Dirk