DNS (Domain Name System) is a system in charge of storing all domain data information on the network. With DNS, the existing domain or hostname will be translated and translated into an IP address so that it can be accessed. This DNS was discovered in 1983 by Paul Mackapetris. Before using DNS, domain mapping used the hosts.txt file.
The hosts.txt file has the disadvantage that when an IP address changes, the file must also change so it is rather complicated. Unlike DNS where changes are dynamic. So if there is a change in a host, then the others will follow, everything will be dynamic. For more details, see the explanation below.
What is DNS Server?
DNS is a server that can serve requests to find out an IP address used by a domain. For example, when you want to access facebook.com, the DNS server will look for the IP address of facebook so that your computer can access facebook.
The use of this DNS server is usually set automatically on every computer and every internet service provider. But if not, you need to set the IP address first. If you use a router, then you can create your own DNS server. However, the IP address lookup is still done by the internet service provider.
From this little explanation, you know the definition of DNS, right? Now the IP address lookup by DNS only needs to be done once. So when the IP address of a particular website is known, the computer will still store it or the term caches DNS so that when accessing the same website, there is no need to search for the IP address again.
DNS Server Function
DNS server is a large database that functions to store all IP addresses used in hostnames. This large database contains a lot of information about IP addres so when you visit a particular website. For example youtube.com, the DNS server will translate or translate it to the youtube IP address.
So that you can connect to youtube and youtube views will come out in your search. In order to better understand the function of the DNS server, we will suppose it is like a phone book on a cellphone. For example, phone number 62857123xxxxx you name A in your contacts. Now when you want to call the number you just select contact A. Later the number in contact A will be contacted so that you can connect to the owner of contact number A.
The phone number here is the same as the IP address and contact A is like a hostname. So when you access contact A, the phone book will translate it into contact A's phone number or when you access a website, the DNS server will translate it into the IP address of the website in question.
DNS management consists of three main components, namely DNS resolvers, recursive DNS servers, and authoritative DNS servers. DNS resolver is a client known as a user's computer that makes DNS requests from certain programs. While the recursive DNS server is the party providing answers to the resolver in the form of the requested DNS search results.
How DNS Server Works
After the recursive searches, the authoritative DNS server appears as the responding party. The response in question can be a delegation or an answer to another DNS server. So simply put, the resolver program (web browser and mail client) will connect the user's computer to the DNS server.
The DNS resolver will look up the host address in the hosts file. If it is found, the data will be provided to the client via the web browser so that the process is immediately completed. In addition to searching the hosts file, the DNS resolver also searches the cache data because IP addresses that have been searched before will be stored in the DNS cache.
So when you visit the same site, the DNS resolver will look for it in the cache data and then provide the results to your web browser so that the process is immediately completed. DNS also looks up the first DNS server address when no data is found in the cache or hosts file. If you have used the above method, but the domain name is not found by the DNS server, then the next search is by searching for files on other database servers.
If it is not found either, then the next search is by contacting other DNS servers that are still related. So the point is that the DNS resolver will first search the cache and hosts file, then if not found, then search the DNS server database. If it is not found, the search will move to the second, third DNS server, and so on until it is found.
Once found, the data will be directly provided to the client through the web browser display. Now, when you can't access a website related to DNS, it is most likely because DNS is unable to find the host.
