Network devices needs to know each other’s IP addresses to communicate. But what if it we had to memorize the series of numbers of all the website IPs we wanted to access? Thankfully, domain names exist, such as nic.br and cidadaonarede.nic.br. They’re much easier to memorize!
That is, it’s much easier for us, users, to memorize. To devices, IP addresses make perfect sense! With just this number sequence, devices can communicate with each other. That’s where DNS, the Domain Name System, comes in. Simply put, the DNS is a large database that contains the link between domain names and corresponding IP addresses. Since the amount of information is very large – there are many devices, IP addresses, and domain names on the Internet – this database is distributed in a hierarchical way among several DNS servers.
There are different types of DNS servers. So that you can understand in simple terms how the translation of names into numerical addresses works, look at these two main types:
- The first type is the recursive DNS, which is responsible for performing queries on the other DNS servers to discover the IP corresponding to a domain name. This is server that your computer or smartphone will consult, when you type, for example, “cidadaonarede.nic.br” into your web browser. In this case, the same server brings the corresponding IP address (2001:12ff:0:4144:f816:3eff:feaf:fac6) and triggers the communication.
- The second is the authoritative server. This one has the authority, that is, the information in fact, about a domain name. It knows the IP addresses corresponding to the domain name researched, or the IP addresses of another authoritative server responsible for a part of the name in the hierarchy. For example, in “cidadadaonarede.nic.br,” an authoritative server is responsible for “.br,” another for “.nic.br” and another for “cidadaonarede.nic.br.”
To connect to the Internet, your computer and other devices, such as the WiFi router, are usually automatically configured with the recursive DNS server address. As a rule, you do not need to manually configure this setting or change it.
https://www.youtube.com/watch?v=ACGuo26MswI&t=0s (portuguese only)
https://www.youtube.com/watch?v=epWv0-eqRMw&t=0s (portuguese only)
In the first scene, a confused man appears looking at various addresses in the IPv4 and IPv6 versions. Above, the phrase “Devices use IP addresses to communicate” appears.
In the second scene, the same man is on the computer and types https://nic.br into the browser. The phrase now is “You don’t need to know the IP address. Use domain names”.
In the third scene, the phrase changes to “The Internet uses DNS to translate!”, while the man types on a computer and it consults a DNS server, asking what the IP for nic.br is, the server searches and responds with the IPv6 version address “2001:12ff:0:4::6”. Finally, as a sign of appreciation, the computer shows a thumbs up.
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