DNS Configuration on Linux (Part 1)

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Domain Name System (DNS) is a decentralized system that translates human-readable domain names into numerical IP addresses that computers can understand. It is an essential part of the Internet, as it allows users to access websites using easy-to-remember names instead of numerical IP addresses.

Consider that we have two systems, A and B.

A and B's IP addresses are

A: 192.168.1.10

B: 192.168.1.11

If two Linux systems are connected to the same network and System A and System B want to interact. We have straightforward commands like

Communication between Systems using Domain names in a Network

With this idea, we are primarily attempting to accomplish the requirement that System 'A' should be able to recognize System B using the domain name 'db' mapped to IP 192.168.8.2.

If System "A" wishes to ping System "B" using a domain name like

An error is initially generated because we failed to set the domain name "db" for IP address 192.168.8.2.

This problem can be fixed by running the Linux code below to add a record.

Now save the file hosts and now try to ping System B using the domain name 'db'.

System A doesn't verify if System B's real name is "db" when System A tries to communicate with System B using the domain name(db). Think about whether "System2" is indeed the name of System B. However, System A does not make that inquiry while interacting with the domain name. System A believes that System B is known as "db" in the host's file.

Disadvantages

If we have a network containing 10 Systems in an organization. Every System contains host's file for each System. If one of the System IPs changes, we need to change the entries in /etc/hosts files of all remaining 9 Systems present in the network.

Connecting a Host to DNS Server

All the entries are collected into a single server, referred to as the "DNS Server," as described in the drawbacks listed above, and all the systems are connected to this server.

Take into account if the DNS server's IP address is 192.168.1.100.

In order to reach the DNS server, we must add an entry to the /etc/resolv.conf file.

After DNS Server Configuration, every time a host comes up across a host name that it does not know about, it looks it up from the DNS Server.

If we have an entry called "sample" in both /etc/hosts and DNS server. The host first checks for the entries in /etc/hosts file after that it checks for entries in DNS Server.

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