Latency and success rate are calculated from measurements of the last 5 minutes.
What Is a Root DNS Server?
Root DNS servers (root servers) are the servers at the very top of the Domain Name System (DNS). When a DNS resolver looks up a domain name such as dnsbil.com for the first time, it first goes to the root servers and learns from them which servers are responsible for top-level domains such as .com, .tr and .net. If the root servers were unreachable, domain names on the internet would stop resolving as caches emptied.
There are 13 root server names, from a.root-servers.net to m.root-servers.net. However, each of them is published from hundreds of points around the world using the anycast method, with the same IP address; your query is routed to the nearest copy on the network. The latency values on this page show how long it took the probes to reach the nearest copy.
List of the 13 Root DNS Servers
How Is This Data Collected?
The data comes from the RIPE Atlas measurement network operated by RIPE NCC, the European regional internet registry. Thousands of small physical devices (probes), placed in volunteers' homes and data centers, send an SOA query to each of the 13 root servers every 30 minutes. The results are published in real time over a public stream; this page processes that stream directly in your browser.
The serial number panel shows which version of the root zone file is being seen. The root zone is usually updated twice a day. When a new version is published, you can watch live how quickly the share of probes that see the old serial number drops within minutes; this is the highest-level example of DNS propagation.
Frequently Asked Questions
Are there only 13 root DNS servers?
There are 13 root server names, but each of them is published from many locations around the world using anycast. In total there are more than 1,900 root server copies.
What do timeouts and an old serial number mean?
A timeout means the probe did not receive a response within 5 seconds; it is usually caused by a problem in the probe's own network. An old serial number may mean either that this root server copy has not been updated yet, or that a network device between the probe and the server intercepted the DNS query and answered it itself.
How much data does this page use?
The measurement stream carries roughly 80–90 KB of data per second. For this reason the stream pauses automatically when the tab is in the background, and after 15 minutes of uninterrupted monitoring; you can resume it with one click whenever you like.