To understand how the internet works, you need to know a few things about domains and domain name servers. A domain is a website address that contains a specific set of letters and numbers. Domain names are added by registrars, who sell them for an annual fee. Once a domain has been registered with a registrar, it is then assigned to one or more DNS servers which will tell any person looking up the site what server they should be connecting to.
Here’s a quick list of the main components that make the internet function:
The DNS System
The DNS system is a global server network that translates domain names into IP addresses. When you type a domain name into your browser, your computer will query DNS servers until it finds the server with the corresponding IP address for that domain name. This process is known as DNS resolution.
Domain Name Servers
Domain name servers (DNS servers) act as intermediaries between domain names and IP addresses. They keep track of all the registered domains and the corresponding IP addresses, and they can respond to queries from clients looking for specific domain names.
Root Zone File
The root zone file is a database that contains all of the top-level domains (TLDs) and their corresponding nameservers. ICANN maintains it, and it is responsible for assigning top-level domains, maintaining the root zone file, and overseeing the DNS system.
An IP address is written with numbers and dots. It’s like the website address you type into your browser. IP addresses are unique to each computer and are assigned by Internet Service Providers (ISPs). When you type a domain name into your browser, your computer will query DNS servers until it finds the server with the corresponding IP address for that domain name.
Top-Level Domain Names
The top level of the domain name system is managed by the Internet Corporation for Assigned Names and Numbers (ICANN). ICANN is a nonprofit organization that was created in 1998 to manage the domain name system and regulate global internet policy. It is responsible for assigning top-level domains, maintaining the root zone file, and overseeing the DNS system.
Within the UK domains are managed by Nominet. Nominet is a not-for-profit organization that manages .uk domain names. They are in charge of assigning top-level domains, maintaining the root zone file, and overseeing the DNS system.
DNS records contain a variety of information, including the following:
– The domain name
– The IP address of the domain name’s web server
– The address of the name server that is responsible for the domain
– The date and time of the last update to the DNS record
– MX Records
– CNAME records
MX records specify the mail service provider for a domain. When someone tries to contact your domain, they will query DNS servers until they find the server with the corresponding IP address, then send their message there.
Canonical Name records (CNAME) create an alias from one domain name to another. The “www” part of a domain is an alias to the root domain. CNAME records are used when setting up a CDN to deliver assets from another server.
Content Delivery Networks (CDN)
Content Delivery Network (CDN) is a content distribution system that serves content to end-users with high availability and high performance. CDNs serve a large variety of data, including text, images, audio, video, software or other digital assets for Internet applications.
A CDN’s goal is to deliver the highest quality experience to end-users. This may be accomplished by ensuring content is delivered without interruption from network congestion or outages, which are often local and global. When deployed on a large scale, CDNs serve content close to where needed, minimizing the distance travelled up to 99% of the time.