What is a DNS and How Does it work?

The abbreviation DNS refers to the Domain Name System can be identified as the phonebook of the internet. One can access the information from the net through the domain name like espn.com, waptrick.com. The IP address is required by the browser to reach the particular site. DNS is the tool that provides the IP address of the domain name to the browser. Each device connected to the net has an IP address that is required by other devices to find it. DNS has made it easy for humans to remember the IP address like 192.168.1.1 and the more tough alpha-numeric IP addresses like 2400.cb00:2048:1:c629 etc.

How DNS Works?

After adding the human-readable address into the browser, the domain name system will check for the address in its memory, if the address is not found then it will check for the address in the local area network.

After the DNS searches the requested address and it is found it returns with the result. If no such address is found the local server will found the IP address in the Internet service provider. As the domain name system contains the temporary store of DNS records, if the address is found in the record then it will quickly provide the result. These DNS servers are not authoritative as they provide resolution cached value gained from authoritative DNS servers. The top-level Domain Name Server provides the list of the authoritative Domain Name servers for all domains. Its task is to check the name servers to find and provide the authoritative name servers of the searched domain.

What Are The Types Of DNS Queries?

In Domain Name System generally, three types of queries exist. With the help of these queries, the whole process of DNS resolution can give a reduction in distance traveled. In normal conditions, recorded data is available which permits the DNS server to return a non-recursive query.

Types Of DNS Queries

The three types of queries are Recursive query, Iterative query, Non-recursive query. These queries are further discussed below.

1. Recursive Query

In RECURSIVE QUERY the DNS client needs a domain server that responds quickly to the client with the required record or with the message if the record is not found.

2. Iterative Query

In ITERATIVE QUERY DNS client allows a DNS server the best solution it can provide. If the DNS server does not have a match for the requested query name it will then refresh it to the authoritative server for the low level of domain space. This whole process continues until the servers down the query chain or the error or timeout occurs.

3. NON- Recursive Query

Non-recursive query outcomes when DNS client queries for the server record with access because of its authority for the record. The DNS server will cache the DNS record to avoid the extra bandwidth consumption and extra traffic on servers.

What Is DNS Caching?

DNS caching is performed to save the client’s time and to provide faster results. DNS caching is the process of storing the data in a location closer to the client which improves performance and reliability. It stores data closer to the user so that the query can be resolved quickly and extra queries chain can be broken, which reduces loading time and lower bandwidth consumption.

Where Does DNS Caching Occur?

DNS caching mainly occurs at two ends. Browser DNS Caching And Operating systems Level DNS caching.

1. Browser DNS caching

Most of the modern web browsers are developed in such a way that Cache records for a set amount of time. The purpose of doing this is that closer the DNS caching occurs to the web browser; the fewer the processing steps must be taken to check the cache and make requests. Whenever the request is made for a DNS record the first location that is checked is Browser cache.

2. Operating System (OS) Level DNS Caching

The second place where DNS Query leaves your device is the Operating system level DNS resolver. The process that is designed to handle this query is known as stub resolver or DNS client.

Whenever a stub resolver gets the request from an application it checks if it has the record in its cache and if it does not have it sends a DNS query outside the local network.

How To Flush DNS Cache?

We have gathered methods to clear your DNS cache for different operating systems and browsers. You can choose the right one for you.

1. In Windows Operating Systems

To clear the DNS cache on Windows operating systems, follow these steps:

1. Open a DOS command window. To do this, press Start, click Run, type cmd, and then press Enter.

2. At the command prompt, type the following flush DNS command and then press enter.

ipconfig/flushdns

3. The DNS cache is now clear.

2. In MAC OS X Operating Systems

To clear the DNS cache on Apple Mac OS X, follow these steps:

1. Open a terminal window. To do this, click Applications, click Utilities, and then click Terminal.

2. At the command prompt, type the appropriate command for your Mac OS X version to clear the cache.

For information about which command you should use for your Mac OS X version, please visit https://support.apple.com/en-us/HT202516.

3. The DNS cache is now clear.

3. In Google Chrome Browser

The Google Chrome web browser maintains its internal DNS cache. To clear it, follow these steps:

1. Start Google Chrome.

2. In the address bar, type chrome://net-internals/#dns. Google Chrome displays a list of hosts in its internal DNS cache.

3. Click Clear host cache.

4. In the address bar, type chrome://net-internals/#sockets.

5. Click Close idle sockets, and then click Flush socket pools.

Final Words

In this post, we have discussed in detail the DNS, its working, types, and flushing process. This guide is enough to learn about DNS. If you still have doubts regarding DNS, then you can surely contact us in the comments section. We will surely help you there.