Have you ever wondered how your computer knows where (which physical server) to go? when you type a web address?
The secret is Marvelous what’s behind the DNS system (Domain Name System).
What will you find here?
It’s the glue that holds the Internet together and makes browsing as easy as it is today.
What is the DNS system and what is it for?
If this were not the case, by accessing, for example, Google, browsing the Internet would not be as intuitive as typing google.com, but would consist of typing IP addresses insmokable for a human (for example: 172.217.10.238) which are i “REAL” Internet server addresses.
However, thanks to the DNS system we will be able to save ourselves from having to deal with these unmanageable numbers and use the Internet effectively much more intuitive and rewarding.
A brief history of DNS
DNS was born out of a need. At the beginning of the Internet era there were a manageable number of servers and a text file called host.txt For map domain names to IP addresses.
But with the growth of the Internet, this method has become unsustainable. So, in 1983, Paul Mockapetris invented DNS to address this expansion and allow for greater scalability.
DNS has been an integral part of the Internet infrastructure ever since.
Components of the DNS system. Types of DNS servers
The DNS system is made up of several key elements. Domain name servers do the heavy lifting, finding and serving the correct IP addresses.
The main components of this system are the following:
DNS server cache or resolver
DNS Cache servers, also known as DNS Resolver servers, are the DNS servers used by your computer or network to send name resolution requests.
These servers do not store domain information, but cache all domain information obtained from other DNS servers to improve the efficiency of future searches.
If they don’t have the requested information in cache, these servers will pass the request to other servers (first to a root server, then to a TLD, etc.) until they get the response.
Root DNS server
Root DNS servers represent the highest hierarchy in the Domain Name System (DNS) structure.
These servers do not store domain-specific information, but rather direct requests to the corresponding top-level DNS (TLD) server. to exist 13 root servers worldwide that ensure global accessibility to the Internet.
Top-Level DNS Server (TLD)
Top-level domain (TLD) servers are one level below root DNS servers in the DNS hierarchy.
These servers store information for the domains that are at their level. For example, a TLD server for .com will know information about the authoritative name servers for google.com, but not necessarily information about www.google.com.
Authoritative DNS servers
Authoritative DNS servers are those that store DNS records for specific domains.
When you set up a domain, you specify which DNS servers will be authoritative for that domain. These servers contain detailed information about the domain, including the IP addresses of the name servers for the subdomains.
How does the domain resolution process work?
The DNS resolution process is like a treasure hunt.
It starts when you enter a domain name into your browser. This sends a query to the nearest DNS server. If the server has the answer, great, it will send it back to you.
If not, it starts a search, asking other servers until it finds the correct answer. This process, although it seems long, occurs in a few milliseconds.
Let’s consider it with the most typical example: accessing a website from a browser.
This would be the process:
- The user types the URL they want to access into the client (the web browser). The operating system extracts the domain from this URL and sends a resolution request to the local DNS configured on the machine.
- The local DNS or resolver resolves the request directly from its cache or forwards it to a root DNS server.
- The root server responds to the DNS resolver with the address of a server for the respective top-level domain (TLD). That is, if we typed “Google. com”it does not directly return the IP of this domain but rather tells the authoritative DNS where to obtain it.
- Finally, the DNS resolver asks the authoritative DNS server for the IP address of the origin server on which the web hosting takes place.
- The DNS resolver obtains the IP address of the origin server from the authoritative DNS server and with this finally accesses the web server of the domain, “Google. com” in our example.
You can see this process reflected step by step in the chart above.
DNS in practice: how to configure DNS
As an Internet user you don’t have to access virtually anything. Simply setting up your Wi-Fi connection for Internet access will be enough. Your computer, cell phone, tablet, etc. It will communicate with the WiFi router and the DNS resolver for your device will be configured automatically.
In the case of creating a web server, when you contract hosting together with the domain, you will not have to worry about configuring your server’s DNS (in this case the authoritative DNS).
Where it is necessary to configure these DNS is in the case of having contracted the domain with one provider and the hosting with another. In this case, you have to do a small (very simple) configuration of the domain’s DNS so that they point to the server that hosts them.
As I said, this is very simple to do and is explained in detail in the post above.
Security and DNS
While DNS is vital to the functionality of the Internet, it is not free from threats. From cache poisoning to DNS hijacking, there are numerous attacks that can exploit DNS weaknesses.
But of course the Internet community has developed various security measures, such as DNSSEC that provides authentication and integrity verification, e DoH Yes Point which encrypt your DNS queries to protect your privacy.
Innovations and future trends in DNS
DNS isn’t stuck in the 1980s, the DNS system is evolving to meet new challenges and opportunities.
For example, Anycast DNS allows DNS servers to be located in multiple locations for greater resiliency and performance. And with the advent of 5G networks, we may see more innovations on the horizon.
Conclusion
DNS is like the invisible pillar of the Internet. Most users are completely unaware of its existence, but without it, browsing the Internet would be an ordeal of having to memorize and write down IP addresses. “infuming” instead of easy-to-remember domain names.
