what is DNS? full detail and how to enable in android

DNS (Domain Name System), DNS comes in the internet system in all over the world, and it as a great roll in the internet world so let check-in brief what is DNS and how we can also take it in use in daily life.

What is DNS?

Domain Name Server (DNS) is a standard protocol that helps Internet users discover websites using human-readable addresses. Like a phonebook which lets you look up the name of a person and discover their number, DNS lets you type the address of a website and automatically discover the Internet Protocol (IP) address for that website.

Without DNS, the Internet would collapse - it would be impossible for people and machines to access Internet servers via the friendly URLs they have come to know.

For example, the domain name www.vikashackerofficial.blogspot.com  you are viewing now, translates to the IP address 104.20.48.182 (in the old IPv4 format) or 2002:6814:30b6:0:0:0:0:0 (in the newer IPv6 format).

In easy words when we search something on the world wide web for example any website so it first goes to DNS and it check-in that from where the website belongs than it sends the IP of that address to our device then the website opens. DNS have 3 main servers where it checks details about any website, so let check what is that 3 main severs which DNS have and it also plays so much importance and the main role in fast browsing.

DNS main servers

There are 3 main severs which have used to resolve a DNS query.

1. Root name server
2. Top level domain server
3. Authoritative dns server

This are the main 3 servers of DNS 

So let get some full details about 3 main severs

Root name server

A root name server is a name server for the root zone of the Domain Name System of the Internet. It directly answers requests for records in the root zone and answers other requests by returning a list of the authoritative name servers for the appropriate top-level domain.

Top level domain server

A TLD (top-level domain) is the highest level of domain names in the root zone of the DNS of the Internet. For all domains in lower levels, it is the last part of the domain name, that is, the label that follows the last dot of a fully qualified domain name. In other words the last part of an Internet domain name that follow the final dot of a fully qualified domain name. For example, in the domain name www.dnsknowledge.com, the top-level domain is com.
Internet Corporation for Assigned Names and Numbers (ICANN) looks after most top-level domain. It operates the Internet Assigned Numbers Authority (IANA) and is responsible for maintaining the DNS root zone. DNS server which keeps all root zone is called TLD name server.

Authoritative dns server

An authoritative name server provides actual answer to your DNS queries such as – mail server IP address or web site IP address (A resource record). It provides original and definitive answers to DNS queries. It does not provides just cached answers that were obtained from another name server. Therefore it only returns answers to queries about domain names that are installed in its configuration system. There are two types of Authoritative Name Servers:

1. Master server (primary name server) – A master server stores the original master copies of all zone records. A hostmaster only make changes to master server zone records. Each slave server gets updates via special automatic updating mechanism of the DNS protocol. All slave servers maintain an identical copy of the master records.
2. Slave server (secondary name server) – A slave server is exact replica of master server. It is used to share DNS server load and to improve DNS zone availability in case master server fails. It is recommend that you should at least have 2 slave servers and one master server for each domain name. 

How do DNS servers resolve a DNS query.

In a typical DNS query without any caching, there are four servers that work together to deliver an IP address to the client: recursive resolvers, root nameservers, TLD nameservers, and authoritative nameservers.
The DNS recursor (also referred to as the DNS resolver) is a server that receives the query from the DNS client, and then interacts with other DNS servers to hunt down the correct IP. Once the resolver receives the request from the client, the resolver then actually behaves as a client itself, querying the other three types of DNS servers in search of the right IP.

And why we should use always Google Dns for best search result speed because when we use default DNS then some website doenst opens or when we open it blocks directly and, we can change dns in both in our pc, laptop, or android device 

Google Public DNS IP addresses

The Google Public DNS IP addresses (IPv4) are as follows:

• 8.8.8.8
• 8.8.4.4

The Google Public DNS IPv6 addresses are as follows:

• 2001:4860:4860::8888
• 2001:4860:4860::8844

You can use either address as your primary or secondary DNS server.

So now how we can change DNS in our pc 

Windows

DNS settings are specified in the TCP/IP Properties window for the selected network connection.

Example: Changing DNS server settings on Windows 10

1. Go to the Control Panel.
2. Click Network and Internet > Network and Sharing Center > Change adapter settings.

3. Select the connection for which you want to configure Google Public DNS. For example:

   • To change the settings for an Ethernet connection, right-click the Ethernet interface and select Properties.
   • To change the settings for a wireless connection, right-click the Wi-Fi interface and select Properties.

   If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

4. Select the Networking tab. Under This connection uses the following items, select Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol Version 6 (TCP/IPv6) and then click Properties.

5. Click Advanced and select the DNS tab. If there are any DNS server IP addresses listed there, write them down for future reference, and remove them from this window.

6. Click OK.

7. Select Use the following DNS server addresses. If there are any IP addresses listed in the Preferred DNS server or Alternate DNS server, write them down for future reference.

8. Replace those addresses with the IP addresses of the Google DNS servers:

   • For IPv4: 8.8.8.8 and/or 8.8.4.4.
   • For IPv6: 2001:4860:4860::8888 and/or 2001:4860:4860::8844.
   • For IPv6-only: you can use Google Public DNS64 instead of the IPv6 addresses in the previous point.

9. Test that your setup is working correctly; see Test your new settings.

10. Repeat the procedure for additional network connections you want to change

for macOS

DNS settings are specified in the Network window.

Example: Changing DNS server settings on macOS 10.15

1. Click Apple menu > System Preferences > Network.
2. If the lock icon in the lower left-hand corner of the window is locked, click the icon to make changes, and when prompted to authenticate, enter your password.
3. Select the connection for which you want to configure Google Public DNS. For example:
   • To change the settings for a Wi-Fi connection, select Wi-Fi, and click Advanced.
   • To change the settings for an Ethernet connection, select Built-In Ethernet, and click Advanced.
4. Select the DNS tab.
5. Click + to replace any listed addresses with, or add, the Google IP addresses at the top of the list:
   • For IPv4: 8.8.8.8 and/or 8.8.4.4.
   • For IPv6: 2001:4860:4860::8888 and/or 2001:4860:4860::8844.
   • For IPv6-only: you can use Google Public DNS64 instead of the IPv6 addresses in the previous point.
6. Click OK > Apply.
7. Test that your setup is working correctly; see Test your new settings.
8. Repeat the procedure for additional network connections you want to change.

Linux

In most modern Linux distributions, DNS settings are configured through Network Manager.

Example: Changing DNS server settings on Ubuntu

1. Click System > Preferences > Network Connections.
2. Select the connection for which you want to configure Google Public DNS. For example:
   • To change the settings for an Ethernet connection, select the Wired tab, then select your network interface in the list. It is usually called eth0.
   • To change the settings for a wireless connection, select the Wireless tab, then select the appropriate wireless network.
3. Click Edit, and in the window that appears, select the IPv4 Settings or IPv6 Settings tab.
4. If the selected method is Automatic (DHCP), open the dropdown and select Automatic (DHCP) addresses only instead. If the method is set to something else, do not change it.
5. In the DNS servers field, enter the Google Public DNS IP addresses, separated by a comma:
   • For IPv4: 8.8.8.8 and/or 8.8.4.4.
   • For IPv6: 2001:4860:4860::8888 and/or 2001:4860:4860::8844.
   • For IPv6-only: you can use Google Public DNS64 instead of the IPv6 addresses in the previous point.
6. Click Apply to save the change. If you are prompted for a password or confirmation, type the password or provide confirmation.
7. Test that your setup is working correctly; see Test your new settings.
8. Repeat the procedure for additional network connections you want to change.

If your distribution doesn't use Network Manager, your DNS settings are specified in /etc/resolv.conf.

Example: Changing DNS server settings on a Debian server

1. Edit /etc/resolv.conf:

   sudo vi /etc/resolv.conf
   

2. If any nameserver lines appear, write down the IP addresses for future reference.

3. Replace the nameserver lines with, or add, the following lines:

   For IPv4:

   nameserver 8.8.8.8
   nameserver 8.8.4.4
   

   For IPv6:

   nameserver 2001:4860:4860::8888
   nameserver 2001:4860:4860::8844
   

   For IPv6-only, you can use Google Public DNS64 instead of the above IPv6 addresses.

4. Save and exit.

5. Restart any Internet clients you are using.

6. Test that your setup is working correctly; see Test your new settings.

Additionally, if you are using DHCP client software that overwrites the settings in /etc/resolv.conf, you need to configure the DHCP client by editing the client's configuration file.

Example: Configuring DHCP client software on a Debian server

1. Back up /etc/resolv.conf:

   sudo cp /etc/resolv.conf /etc/resolv.conf.auto
   

2. Edit /etc/dhcp/dhclient.conf (or /etc/dhcp3/dhclient.conf):

   sudo vi /etc/dhcp*/dhclient.conf
   

3. If there is a line following request with only domain-name-servers, remove that line.

4. If there is a line containing domain-name-servers with IP addresses, write down the IP addresses for future reference.

5. Replace that line with, or add, the following line:

   For IPv4:

   prepend domain-name-servers 8.8.8.8, 8.8.4.4;
   

   For IPv6:

   prepend domain-name-servers 2001:4860:4860::8888, 2001:4860:4860::8844;
   

   For IPv6-only, you can use Google Public DNS64 instead of the above IPv6 addresses.

   Note: ISC DHCP v4.3.6 or higher is required for IPv6 domain-name-servers to be processed; earlier versions would silently ignore such configuration.

6. Save and exit.

7. Restart any Internet clients you are using.

8. Test that your setup is working correctly; see Test your new settings.

All this dns changing setup is provided no there official website https://developers.google.com/speed/public-dns/docs/using

Now how we can change DNS in android device because DNS changing supports in 

Android 9 (Pie) or higher

So how we can use any custom DNS in any android version so check out this video and watch till end and, start using custom DNS for better speed searching.