DNS Cache also cited to as DNS resolver cache. It is a temporary database that is maintained by our computer’s operating system. This cache preserves the records of all the recent visits, attempted visits and various other internet domains for the first time visitor. When we revisit that cached web domain it loads quickly without sending an HTTP request to the server.
In short, the aim of DNS cache is making the internet surfing better for users by making the subsequent requests fast to the same hostname.
Windows operating system stores positive response in the DNS cache for 1 day while the negative response is stored for 5 minutes. Apart from Windows, there are many other operating systems such as Mac, Ubuntu that manage this temporary database.
Though DNS cache helps in offering faster internet experience yet sometimes it can go opposite to its nature and cause internet connectivity issues, computer viruses, and other glitches. However, by flushing out your DNS cache you can easily deal with these issues. If you don’t know how to flush DNS, read out this amazing tutorial available in Hostinger.com.
In this post, we will throw some light on the purpose of DNS, how it works and how it can turn into a threat if not deleted at the time.
The Purpose of DNS Cache
As we mentioned in the beginning, DNS cache eases the internet experience by providing the fast access to web domains as it creates a temporary database of recent visits.
To understand the actual role of DNS cache, first, we will have to learn what domain name system is.
Domain Name System (DNS) is an internet service, which interprets domain names into IP addresses. Since domain names are alphabetic, they are easier to remember for humans. However, the internet is based on IP addresses. Every time, we access a domain name, DNS System translated that alphabetic domain into IP address.
For instance, if you type www.example.com into your browser, it might be translated to 126.96.36.199. You can think of DNS like a phonebook. We need not remember everyone’s contact number with a phonebook. In a similar way, with DNS, we need to memorize the IP addresses of every website.
Indeed, Domain Name System helps internet in maintaining the index of websites and their IP addresses. Let’s understand the whole process of DNS.
If you type in google.com in your browser, first your browser will ask your router for the IP address. Your router has a DNS server address stored. Therefore, it just asks the DNS for the IP address of the hostname. DNS server will look for the IP address belonging to google.com. After that DNS server will be able to understand that you are looking for google.com. After that, your browser will load google.com
This process is same for every website you visit. Every time when you visit a site, your browser will initiate a request to the internet. This request will have to wait until the domain name is interpreted into an IP address. Now here, DNS cache comes into play.
The DNS cache speeds up this whole procedure by handling the name resolution of the web addresses visited in recent past. The DNS cache loads the website before the request is sent out to the internet. In actual, DNS caches is available at every scale of the ‘lookup’ process which speeds up website load time.
Let’s find out how DNS Cache Works.
How DNS Cache Works
We are sure now you are pretty much aware of the functionality of DNS cache. Before your browser sends requests to any outside network, your computer looks for the domain name in the local DNS cache database where the list of recently visited domain names and addresses is available.
Windows users who want to view the content located in their local DNS cache can use the command: ipconfig/displaydns. The result will show the record of data length, record name, record type, section, etc.
How DNS Cache Can Turn Into Trouble
As you know, DNS cache preserves the record of recently visited domain names, but unfortunately, it is not sensitive to unauthorized and bad domain names. As a result, it can insert invalid DNS entries and become poisonous. There can be various reasons for DNS cache poisoning such as administrative accidents, malware attacks, computer viruses, etc.
DNS Cache Poisoning Can Cause the Following Issues
A threat to your Personal Security-
Probably, you never saw it from this angle, but it is true that DNS cache can become a threat to your privacy. As you know, the DNS cache keeps the record of every website you visit. It means the websites having confidential and objectionable content are not exceptional.
Anyone who has access to your desktop or laptop can easily look at your DNS cache and find which websites you visit and what content you see. As we said in the previous section, having a look DNS is not a tough job, it can be launched simply by entering the ipconfig/displaydns in the Windows command prompt
So, to avoid security threat, you should clear your DNS cache. It becomes a must-do thing if you use a public computer that is used by multiple users.
It can make your browser abode of Bad IP responses-
DNS cache does not have any provision for separate listing of poor IP responses. Therefore, all the bad connections get chunked with the good ones, resulting in poor performance. Sometimes, it can bring internet connectivity issue as well. By flushing DNS cache, you just not eliminate the bad entry but also remove malware and other viruses.
It can Muddle the Performance of your computer Applications-
Invalid records, bad entries inserted into your DNS Cache can disturb the performance of your desktop applications. By eliminating DNS cache, you can speed up the overall performance of your system.
Do you flush DNS cache time to time? Do share your experience with us in the following comment section.