DNS stands for Domain name system, which translates a simple domain or website name into a machine-readable form that is called IP.
Basically DNS system helps us to search any website without knowing its IP address for example yoursystem.in, without knowing its IP you can easily search.so that is how it is both helpful for humans and machines.
Types of DNS
To being honest, there are millions of DNS servers all over the internet and it is impossible to calculate them but there are 13 DNS server that is called root DNS which contain the whole global database on it.
Mainly there are two types of DNS servers
- Primary DNS Servers
- Secondary DNS Servers
1.primary DNS server
THE primary DNS server is the main server where it collects and reads the data from the domain zone file, This primary server also responsible to send the files on the secondary server.
When a primary server transfers domain zone info from one server to another, it is called as Zone transfer or Zone relocation. zone information is written by the administrator who allows the server that how to behave with other servers. The primary reason for this is to make the admin’s life easier by having double the security due to multiple servers and also to create a backup. Once a primary server is created and zone data is copied, there is actually no need for backup, since all of this is taken care of already because of the primary server by default copies all this data to the secondary server every time.
2.Secondary DNS server
THE secondary DNS server is called a slave server its only work to capture or save the data of the primary server is acting as a backup server.
How its work
The Domain Name System (DNS) is the phonebook of the Internet. Web browsers interact through Internet Protocol (IP) addresses. DNS translates domain names to IP addresses so browsers can load Internet resources. Each device connected to the Internet has a unique IP address that other machines use to find the device.
Address record. A Records map server IP addresses to domain names. For example, 220.127.116.11 to amazon.com.
Canonical Name record. A CNAME record establishes one domain as an alias to another (thereby routing all traffic addressed to the alias to the target; the canonical address).
Like a CNAME record, Alias records can be used to map one address to another. But Aliases can coexist with other records using the same name.
Mail Exchange Record. These records will redirect a domain’s email to the servers hosting the domains user accounts. Mail exchange records are used for determining the priority of email servers for a domain.