The Domain Name System (DNS) is a system used to translate human-readable domain names into IP addresses that computers use to identify each other on the internet. The DNS check process involves various types of DNS servers, including authoritative DNS servers that store DNS records for specific domain names, recursive DNS servers that perform DNS resolution for client devices, and root DNS servers that provide the top-level domain (TLD) information.

The DNS process involves a series of steps, starting from the client device sending a DNS query to a recursive DNS server, which then queries authoritative DNS servers for the requested domain name's IP address. Once the IP address is obtained, it is returned to the client device, allowing it to establish a connection to the correct web server hosting the domain.

The best DNS servers can vary depending on factors like geographic location, network configuration, and personal preferences. Some popular and widely used public DNS servers include Google Public DNS, Cloudflare DNS, OpenDNS, and Quad9. It's recommended to choose DNS servers that are reliable, fast, and offer additional security features.

If a domain name does not exist or is not registered, DNS resolution will fail, and the DNS server will return an error, indicating that the domain name could not be resolved. Users attempting to access the website associated with the non-existent domain name will receive an error message or a "404 Not Found" page.

DNS uses both UDP (User Datagram Protocol) and TCP (Transmission Control Protocol) for communication, and it typically uses port number 53 for both protocols. UDP is used for most DNS queries, while TCP is used for larger DNS responses that do not fit within the limits of UDP. However, DNS over HTTPS (DoH) and DNS over TLS (DoT) are also gaining popularity, which use different port numbers (e.g., 443 for HTTPS).

DNS failure refers to a situation where the DNS resolution process fails to resolve a domain name to its corresponding IP address. This can occur due to various reasons, such as DNS server issues, misconfiguration of DNS records, DNS cache problems, network connectivity issues, or domain name not being registered. DNS failure can result in websites or other network services associated with the domain name being inaccessible or not functioning properly.

A DNS resolver is a component of the DNS system that is responsible for resolving domain names to IP addresses. When you enter a URL or click on a link, your computer's DNS resolver sends DNS queries to DNS servers to resolve the domain name in the URL to its corresponding IP address, allowing your computer to establish a connection to the web server hosting the domain.

DNS records are used to define how domain names should be resolved to IP addresses and other settings. You can configure DNS records for your domain through your domain registrar's or web hosting provider's control panel, by adding or modifying DNS records such as A records, CNAME records, MX records, etc., based on your requirements.

DNS cache is a temporary storage of DNS information on a local device or DNS server to speed up DNS resolution for subsequent requests. DNS cache can affect your website if there are stale or outdated DNS records cached, leading to DNS resolution issues or incorrect website access. Clearing DNS cache or waiting for cache expiration can help resolve such issues.

DNSSEC (Domain Name System Security Extensions) is a suite of extensions to DNS that adds an additional layer of security by signing DNS data with cryptographic signatures. DNSSEC helps prevent DNS spoofing, man-in-the-middle attacks, and other DNS-related security threats, ensuring the integrity and authenticity of DNS data.