What is a DNS?
By Prempal Singh
Most Internet users know that the DNS server translates website names into IP addresses. And usually this knowledge of the DNS server ends. This article is designed for a more in-depth consideration of its functions.
So, let’s imagine that you have to debug the network for which the provider allocated a block of “honest” addresses, or set up to raise your DNS server in the local network. Here all terrible words will immediately appear, such as “zone”, “transfer”, “forwarder”, “in-addr.arpa” and so on. Let’s gradually deal with this all.
In a very abstract way, it can be said that every computer on the Internet has two main identifiers — the domain name (for example, www.imena.ua) and the IP address (for example, 127.0.0.1). But the abstractness lies in the fact that the computer can have several IP addresses (moreover, each interface can have its own address, and in addition several addresses can belong to one interface), and there can also be several names. And they can communicate with one or several IP-addresses. And thirdly, the computer may not even have a domain name.
As mentioned earlier, the main task of the DNS server is to translate domain names into IP addresses and back. At the dawn of the birth of the Internet, when it was still ARPANET, this was decided by keeping long lists of all computer networks. At the same time, a copy of such a list should be on every computer. Naturally, with the growth of the network, this technology was no longer convenient for users, because these files were large, and they also needed to be synchronized. By the way, some such “echoes of the past” of this method can still be found now. This is how you can add the addresses of servers that you regularly work with to the HOSTS file (in both UNIX and Windows).