What is a DNS Server?

A DNS server is a component of the Domain Name System. The DNS is one of the two main namespaces on the Internet. When a visitor types in a domain name, a name server returns the address that the visitor is looking for. DNS servers are resolvers, precursors, caches, or root name servers.

DNS resolver

DNS resolvers are used to resolve domain names. This software receives a website URL and retrieves the IP address. The DNS resolver will return this information to the client. A DNS resolver is also referred to as a recursive resolver. The DNS resolver queries the Authoritative Name Servers directly rather than going through the DNS Root Servers.

A DNS resolver responds to DNS queries by querying a database of Authoritative Name Servers. The DNS resolver will then pass the domain name and TLD to the correct server. The server that responds will then display the content requested by the web browser. The DNS resolver is separate from the DNS cache feature you configure in DNS profiles.

DNS resolvers can be either recursive or nonrecursive. A recursive resolver makes several requests before finding the authoritative DNS name server. This may be advantageous in some situations but is not always necessary. DNS resolvers can also use caching to short-circuit multiple requests by serving the requested resource record earlier in the DNS lookup.

DNS root name server

The DNS root name server is the basis of all Internet name resolutions. Hundreds of servers answer requests to the root zone. The leading 13 servers are based in the United States and Europe. They all have an IPv4 address. These servers are operated by ICANN, the Internet Corporation for Assigned Names and Numbers.

Dedicated root servers are also available for rent through a hosting web service. DNS root servers can be used to resolve any domain name. These servers are known as “root servers” because they are at the root of the DNS hierarchy. If these servers were unreachable, resolvers would have difficulty finding websites.

A DNS root name server translates domain names into IP addresses. It is the first server a recursive server will send a query to if it does not have a cached answer. The root name server is an index of all the servers that will hold the information. The Internet Corporation for Assigned Names and Numbers oversees the DNS root name servers. The root name server will direct a client’s query to other name servers that will provide information about the IP address they need to access a website.

DNS precursor

A DNS precursor is a server that performs domain name resolution. It does this by submitting multiple queries to different lower-level DNS servers. The response it receives is then sent to a web browser for processing. Ultimately, a web browser displays the site that was requested. This process is performed billions of times per second. The DNS precursor is helpful when a web browser’s cache is not cleared after a DNS lookup.

When a DNS precursor is used to resolve domain names, it can improve response time by reducing the number of requests. DNS precursors also feature stateful multiplexing to ensure the best security. In addition, the precursor can respond faster to subsequent client requests using connected UDP sockets.

A DNS precursor is usually the default resolver for an ISP. It has additional functionality that depends on the contents of the cache. Most web browsers and operating systems will indulge in DNS caching to keep online performance high. The cache contains small files and data that keep the load time down. It can also help reduce the time required to perform a DNS lookup. The cached information is then sent to a precursor server.

DNS cache

A DNS cache is a storage space where a DNS server stores information about addresses for a given period. This information is helpful for browsers and operating systems as it speeds up the retrieval of search results. The length of the cache is adjustable, from two seconds to thirty days. You can also specify a minimum or a maximum number of seconds, which helps speed up the retrieval of search results.

Although DNS servers are a common component of Internet services, they serve several different roles. For example, a recursive server tracks down a list of requests made by a client, zeroes in on a specific name server, caches the complete answer and returns it to the client. DNS caches are useful for applications, but not all of them can follow the standard DNS specification.

The DNS system implements time-to-live (TTL) for every DNS record. The TTL value specifies the number of seconds a DNS record can be cached. Once the TTL value has been reached, the DNS server has to start the resolution process.