Dear colleagues, As you are probably aware, DNSMON* and RIPE Atlas built-in** measurements are often used when analysing outages and other issues with important DNS services, particularly the root zone servers. These measurements do not provide a direct indication of the impact on actual end-user experience because they involve directly querying authoritative name servers, thereby ignoring the effects of having multiple authoritative name servers as well as caching local recursive resolvers. To improve upon our DNS monitoring, we will initiate two built-in DNS measurements from all RIPE Atlas probes that use the probes' default resolvers instead of authoritative name servers. The first measurement will query for random top-level domains with the intention of avoiding caches and therefore hitting at least one root name server. The second measurement will query for popular domain names, with the intention of hitting caches where appropriate and getting an idea of the true impact on users. As a starting point for the second measurement, we will use a recent snapshot of the global top 50 visited sites according to the Alexa top sites list***, which combines unique visitors and individual page views in its calculations. Probes will cycle through these domains, querying for a different A record every 10 minutes. Since DNS queries containing these domains will be made from every connected RIPE Atlas probe, we would like to ask for feedback on whether querying the DNS for any of these domains could pose legal or political problems for probe hosts in certain parts of the world. I have also included the next 25 most popular domains below, which will be used to fill any gaps caused by removing items from the main list. Kind regards, Chris Amin RIPE NCC * https://atlas.ripe.net/dnsmon/ ** https://atlas.ripe.net/docs/built-in/ *** https://en.wikipedia.org/w/index.php?title=List_of_most_popular_websites&oldid=762455912 Provisional 50 domains to query =============================== google.com. youtube.com. facebook.com. baidu.com. wikipedia.org. yahoo.com. google.co.in. amazon.com. qq.com. google.co.jp. live.com. taobao.com. vk.com. twitter.com. instagram.com. hao123.com. sohu.com. sina.com.cn. reddit.com. google.de. linkedin.com. tmall.com. yahoo.co.jp. weibo.com. google.fr. 360.cn. google.co.uk. google.ru. google.com.br. yandex.ru. ebay.com. bing.com. msn.com. google.it. soso.com. t.co. wordpress.com. google.es. microsoft.com. tumblr.com. aliexpress.com. blogspot.com. netflix.com. amazon.co.jp. ok.ru. google.com.hk. stackoverflow.com. google.ca. google.com.mx. imgur.com. Next 25 most popular domains, excluding pornography =================================================== apple.com. Naver.com. mail.ru. imdb.com. popads.net. onclickads.net. office.com. google.co.kr. github.com. pinterest.com. paypal.com. tianya.cn. google.com.tw. google.com.tr. google.com.au. diply.com. amazon.de. google.co.id. microsoftonline.com. onclckds.com. twitch.tv. adobe.com. amazon.co.uk. wikia.com. cnzz.com.