- Online DNS Lookup Webapp for interacting with name servers. Specify query (name and type), name server IP address, recursive / iterative resolution.
- The Internet Domain Name System Explained for Non-Experts by Daniel Karrenberg
- Wireshark Packet Captures Collection by Chris Sanders.
Root name servers
- Root Name Servers The 13 root name servers are operated by 12 independent organisations.
- Each IP address used for root name servers actually corresponds to many different servers, thanks to a technology called anycast that we will not study in this course (thus the number of root name servers is much greater than 13). This interaction with ChatGPT provides an overview of how anycast works.
- Root Name Servers Traffic Count of queries made to root name servers (daily averages): They are in the order of hundreds of billions queries every day.
Statistics on DNS size
- Domain Name Industry Brief - Dashboards Dati statistici sulla dimensione del DNS.
- DNS Zone Stats On this page you can find links to graphs displaying the total domain count per TLD zone.
Domain creation (Registry, Registrar, Registrant)
If you want to "create a domain" under a certain TLD, you have to contact a "DNS provider" able to create domains below that TLD, e.g., Misterdomain is able to create domains below
.com and several other TLDs.
In DNS parlance, domain creation is done by registrars. A DNS provider is a registrar or a reseller of a registrar. The owner of the newly created domain is called registrant. The organization that manages the TLD is called registry. A broader definition of these terms is given in this ChatGPT interaction.
The registry for
.it is "Registro .it - Istituto di Informatica e Telematica del CNR - Via G. Moruzzi, 1 - 56124 Pisa" (i.e., this organization manages the
In this paper we examine the dependence of a large set of public administration websites on DNS entities and autonomous systems for four different countries: Italy, Germany, UK and US. We collected the dependencies of those websites from DNS zones, nameservers, networks and assessed the potential global impact of localized attacks on those entities:
- How many websites have redundant name resolution paths? What redundancy level is used at the level of zones, nameservers, networks?
- How many websites could be affected, whether in name resolution or web server access, by an attack on a single zone, nameserver, network?
- How prevalent is the usage of groups of IP addresses, networks for providing redundancy? How many websites could be affected by an attack to one of those groups?