Nameservers are vital for domain functionality but some users do not understand what nameservers are. This article will explain it in simple words.
Nameservers: backbone of the Internet
There are two interconnected parts of the Internet, the alphanumerical space of domain names (website names like DomainName.com or Facebook.com) and numerical space of resource addresses – IP addresses of the websites. Nameservers are special network solutions, consisting of both hardware (servers) and software. Their purpose is to transform text queries for domain names done by humans into IP requests network protocols understand.
This is done by using DNS zone files, containing information of the location (IP address) of each domain and service currently existing. Such zone files exist on every nameserver, there purpose is enabling storing and updating domain name settings and details. Therefore, when making any updates for your domain – setting an IP (A record), URL forwarding, Email forwarding, etc. – you actually make changes in its zone file, stored at some nameserver.
When your domain is registered, it is pointed to certain nameservers, usually to Registrar defaults. It means its DNS zone file is located there and all domain operations are made from your account with that company.
When you decide to launch a website or create email service for your domain, you purchase a hosting package for it. In order to become operational this package needs to be connected with your domain. Usually it is done with pointing by A record (IP address) and CNAME record or by completely changing nameservers for the domain. It involves DNS propagation, causing website downtime from several minutes up to 24-72 hours.
Please note, that if you decide to change nameservers to hosting ones, domain DNS zone file will be stored there and you will need to manage your domain from under your account with hosting company. On the opposite, if domain is pointed to hosting nameservers only by A record and/or CNAME record, its zone file remains on Registrar default nameservers.
If you yet do not have a hosting package during domain registration, feel free to leave nameservers as default (ns1,2,3.domainname.com in our system). You can always change nameservers later.
Main types of nameservers
Sum of all DNS zone files stored on nameserver is called its zone of authority. Root nameservers owned and managed by ICANN have the biggest zone of authority, as they are able to route any request to the right location. Thus said, root nameservers are the key element of modern Internet, the backbone of the system. There are several kinds of nameservers and each one plays an important role. The types are:
Actually each nameserver can work in all three ways. Short description of each type is given below.
This type of nameservers is the most important, as it can perform the DNS query. In short, whenever you want to visit a website and type it’s name in your browser’s address bar, your browser should find the website’s IP address to be able to connect with it. The process of this search is called DNS query and answering these requests is the main goal of authoritative nameservers.
Main types of such nameservers are root nameservers, owned by ICANN and Registry nameservers, owned by certain Registries. They operate billions of requests per minute and carry the main load of Internet functionality. These nameservers are able to do this, because they are the highest level of the hierarchy and can locate any DNS zone file, stored in their zone of authority.
Any nameserver can actually act as recursive. Whenever it receives a DNS query request it cannot answer (because target zone file is not in nameserver’s zone of authority), it reroutes this request to a higher-level nameserver (Registry or root). Any nameserver also acts as authoritative in case it has the requested record (IP address of the website you are after) in one of its DNS zone files (zone of authority).
Nameservers provided by domain Registrar and/or hosting companies (like DomainName.com) by default act both as authoritative and recursive, thus enabling domain and hosting service functionality.
Any record on the Internet has TTL(Time to Live). This allows checking its validity once a certain period of time, not every second. This greatly decreases overall load on nameservers, thus improving their performance. Stored after previous check information, valid until its TTL expires is called cache memory. This type of data is mostly stored on caching nameservers, owned by Internet Service Providers (ISPs) worldwide.
Thus said, when you access any web page regularly (more often than its record’s TTL), this information is cached on your ISP’s nameservers and DNS query does not go further than there. This greatly decreases response time and improves overall customer experience.
When you want to visit a website you never visited before, DNS query will go all the way up the hierarchy, to Registry or even root nameservers, until requested IP address is found in one of their zone files. This information will then be given to your browser and cached for further usage. Thus said cache memory is always updated to contain only valid data.
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