What is DNS (Domain Name System)?
The Domain Name System is the telephone book of the Internet. Humans can access online information through domains like nytimes.com and espn.com. Internet Protocol addresses are used by web browsers to interact. DNS converts domain names into IP address, so that browsers can access Internet resources.
Every device connected to Internet has an IP address that other machines can use to locate the device. DNS servers eliminate the need for humans to memorize IP addresses such as 192.168.1.1 (in IPv4), or more complex newer alphanumeric IP addresses such as 2400:cb00:2048:1::c629:d7a2 (in IPv6).
What is DNS?
DNS resolution is the process of converting a hostname, such as www.example.com, into an IP address that can be read by computers (such 192.168.1.1). Each device on the Internet is assigned an IP address. This address is needed to locate the device, just as a street address can be used to locate a specific home. A user must translate the address they type into their browser (example.com), to the machine-friendly one needed to find the example.com website.
To understand how DNS queries are resolved, you must first learn about the hardware components that the DNS query passes through. The DNS lookup is done “behind-the-scenes” by the web browser and does not require any interaction from the computer other than the initial request.
Report
Report on 2025 Security Signals
There are four DNS servers that play a role in the loading of a website:
- The DNS recursor– A recursor is like a librarian that has been asked to find a book in a library. DNS recursors are servers that receive requests from clients via applications like web browsers. The recursor will typically make additional requests to answer the client’s DNS request.
- Root Nameserver– The Root Serveris the first step to translating (resolving), human readable host name into IP addresses. The root server can be compared to an index of books in a library. It is used to refer to more specific locations.
- nameserver– The top level server (TLD), can be compared to a particular rack of books within a library. This nameserver is used to search for an IP address and hosts the hostname’s last part (in example.com the TLD server would be “com”).
- The authoritative nameserver This nameserver is like a dictionary in a book rack, where a name can be translated to its definition. The authoritative nameserver will be the last nameserver to answer the query. The authoritative nameserver will only return the requested IP address if it has the record.
Fast and Secure DNS
Cloudflare plans include free DNS
What is the difference between a DNS resolver and an authoritative DNS server?
The two concepts are both servers (groups) that form the DNS infrastructure. However, each concept has a distinct role to play and is located in a different place within the DNS query pipeline. The recursive solver is located at the start of the DNS query, while the authoritative nameserver resides at the end.
Recursive DNS resolver
Recursive resolvers are the computers that track down the record when a client makes a recursive query. This is done by making multiple requests until the DNS nameserver that holds the authoritative record for the record requested (or returning an error or timeout if the record cannot be found). Recursive DNS resolvers don’t always have to make multiple requests to find the records they need to respond to clients. caching, for example, is a data-persistence process that can help shorten the number of requests needed by serving up the resource record requested earlier in the DNS search.
Authoritative DNS servers
An authoritative DNS server, in simple terms, is a DNS server that is actually responsible for DNS resource records. It is the DNS server that answers the query with the resource record. This allows the web browser to get the IP address to access the website or other resources. A nameserver that is authoritative can answer queries using its own data, without having to consult another source. It is the last source of truth in certain DNS records.
In cases where the query is for subdomains such as foo.example.com, or blog.cloudflare.com an additional nameserver is added to the order after the authoritative nameserver. This nameserver is responsible for the subdomain’s CNAME record.
Cloudflare’s DNS service is different from many others. DNS recursive solvers are installed in data centers by different DNS recursive resolutions, including Google DNS and OpenDNS. Comcast also has DNS recursive resolved. These resolvers are designed to provide quick and easy queries by using clusters of DNS optimized computer systems. However, they are fundamentally distinct from the nameservers hosted at Cloudflare.
Cloudflare hosts infrastructure-level nameservers, which are essential to the operation of the Internet. Cloudflare hosts the F-Root server network, which is a good example. The F-root, a component of DNS root level nameserver infrastructure responsible for billions of Internet queries per day, is part of Cloudflare’s a href=”https://blog.cloudflare.com/f-root/”>f-root server network/a>. Our Anycast network allows us to handle high volumes of DNS traffic with no service interruption.
What are the steps involved in a DNS search?
In most cases, DNS is used to translate a domain into an IP address. It is helpful to trace the DNS lookup from the web browser through the DNS process and back. Take a look at these steps.
Note: DNS lookup data is often cached locally on the computer that queries the DNS or remotely within the DNS infrastructure. A DNS lookup usually involves 8 steps. The DNS lookup is faster when DNS information has been cached. This example shows all 8 steps if no DNS information is cached.
There are 8 steps to a DNS search:
-
- The user enters ‘example.com’in a web browser. This query is sent to the Internet, and received by the DNS recursive solver.
- The resolver will then query a DNS root server (. ).
- The root server will then reply to the resolver by providing the address of the Top Level Domain DNS server, such as.com and.net. This server stores all the domain information. Our request for example.com is directed to the.com domain.
- The resolver will then send a request to.com.
- The TLD server will then reply with the IP address for the domain nameserver example.com.
- The recursive solver will send a query to a domain nameserver.
- Nameservers return the IP address of example.com to the resolver.
- The DNS resolver will then provide the IP address requested by the browser.
The browser can request the website once the DNS lookup has returned the IP address of example.com.
- The browser sends a HTTP response to the IP address.