Domain Name Server basics and how DNS works?.
What is DNS?
DNS stands for Domain Name System sometimes also called Domain Name Server or Domain Name Service is used to translate human-friendly Domain Names(e.g devopsmyway.com) to IP address(eg – 10.10.1.1) and Vice Versa.
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Before starting to talk about “how Domain Name Server Works?’”, let’s go through some basic terms:-
What is an IP Address?
IP Address is used by network hosts to communicate with each other. Every Servers/network devices have their own IP addresses.
IP Addresses are of two Types :
IP V4 – It is a 32-bit field containing four blocks
eg. – 18.104.22.168
IP V6– It is a 128-bits field containing 6 blocks
eg. – 2404:6800:4002:807::200e
What is the Top-Level Domain?
The last word in the name of your domain name represents Top Level Domain and the second last word represents Second Level Domain.
Hence .com in google.com is Top Level Domain and .com in amazon.com.au is the Second-Level Domain.
Domain Registrar is an authority that assigns domain names under one or more top-level domains. In other words, we purchase our domains from a Domain Registrar. Some popular Domain Registars are GoDaddy, Amazon, NameCheap, BlueHost, and HostGator, etc.
Domain Registrar registers a domain with InterNIC, a service of ICANN, which enforces the uniqueness of Domain Name across the world.
Start of Authority(SOA) Record
Start of Authority(SOA) record is created in the DNS Zone when we purchase a Domain Name from a Doman Registrar.
Start of Authority record stores information about the Name of the Server, default no of second for Time to Live (TTL), and administrative information(such as email address) about the Zone.
NS Record Stands for NameServer Record, and this record is used by Top Level Domain to route the traffic to Content DNS Server. Content DNS Server contains the Authoritative DNS record.
How DNS works?
Let’s understand “How DNS works ?” using the following diagram.
User request for a Website from his/her browser and the request reaches to Top Level Domain (eg.- .com,.edu,.net )
Top-Level Domain looks for the NS Record for the website. Every domain is pointed to Name Server/Host.
Note: Whenever we purchase a Domain, we need to point our Domain name to a list of Name Servers(e.g ns1.godday.com, ns2.goddady.com, etc.) provided by Hosting Service( Godaddy, BlueHost, AWS, Big Rock, etc) in our Domain Register login.
NS Record gives information about SOA record and SOA record contains information of all other Resource Records( eg.- A Record, CNAME Record, etc.)
Hence the user able to browse the website.
Let us learn some basics about other resource records.
A Record is a type of DNS resource record that is used to translate domain name(Hostname) to an IP address.
A Record’s are translated as follows:
devopsmyway.com ——————-> IP Address
www.devopsmyway.com ————->IP Address
CNAME Record is a type of DNS resource record that is used to translate a domain name to another domain name.
CNAME Records are translated as follows :
devopsmyway.com —————> devmyway-202789234-us-west-2.elb.amazonaws.com
PTR Record is a type of DNS resource record that translates IP address to domain name/Hostname.
PTR Records translates as follows
IP Address ————> devopsmyway.com
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