What is DNS | How does DNS works ?

What is DNS?

Human being around the world get information on the internet through domain names, for example google.com, yahoo.com, or bing.com.

The information they get are from web browsers that interact through Internet Protocol (IP) addresses, Domain Name Servers (DNS) translates this domain names to IP addresses&so web browsers can load the information or internet resources requested by a user.

Simply put, Domain Name Servers (DNS) are like phonebook of the internet, and they are means by which information sourcing on the internet is made easier.

How does DNS works?

Since each device connected to the Internet has a unique IP address which other machines use to find the device.

With DNS servers, there is no need to save or store your IP address which can be  IP addresses such as 191.166.1.0 (if you are using IPv4), or if you are using a more complex modern alphanumeric IP addresses such as 2101:cc01:2014:1::a629:d7c2 (if you are using IPv6). This implies that when you type in a web address, e.g., www.busy.com, your Internet Service Provider will see the DNS associated with the domain name, translates it into a machine friendly IP address (for example if 216.168.224.70 is the IP for glovermail.com) and directs your Internet connection to the correct website.

This procedure is the crucial piece of how the internet works and for nearly everyone using the internet, this is a common scenario. The less obvious fact is that using the DNS resolvers provided by your Internet Service Provider can cost you your privacy.

What is a DNS Leak?

Seeing that no Internet Service Provider has the power to favor one source over another, and are at times forced to give up personal resolving hosts, and DNS-related information of customers when requested of them, this shows that keeping your data private is a lot harder.

A DNS leak is the act of monitoring, storing and filtering your DNS traffic at Internet Service Provider level — by inspecting the public DNS servers you use to resolve internet hostnames into IP addresses.

A DNS leak usually happens when you are using a VPN or some other encoded network and your own public IP address can be seen by all whenever you are making a DNS query. A DNS query usually happens when you are trying to change a URL (for example google.com) to an IP address, which is what happens when you type in a URL into your browser.

How DNS Leak works?:

•  Open up your browser.
•  Type “Google.com”.
•  At this point, your ISP DNS servers will store a record in their servers with this activity:
•  The originating computer IP (yours).
•  The target hostname.
•  The target server IPs.

This means that a DNS leak is a security challenge that happens between the DNS resolvers and your computer; this will affect your online privacy because all enquiries are sent through an encoded DNS request over the network.

Causes of DNS Leak

DNS leaks can happen for many reasons. Some of which are listed below:

•  Your VPN is manually configured. If you’re manually configuring a VPN connection, the risk of DNS leaks is higher and depends on your exact operating system configuration.
•  An attacker controls your router, such as a malicious Wi-Fi operator at a coffee shop. A skilled attacker (which can be a hacker or a spy) may be able to manipulate your device into sending DNS traffic outside of the protection and security of the VPN.
•  Manual DNS setup. You (or maybe software on your device) specifically told the operating system you are using to use specific DNS servers. Power users can ask for a particular DNS service, but due to the security challenges it proffers, it’s probably undesired for many users.

How to test if your DNS leaks?

•  Run an online test: These online tests usually yield quick results, but be aware that some of the most popular VPN companies are the same ones who developed these DNS leak testing tools. Know that they could manipulate results to reflect their own interests, to sell you their own VPN services
•  Run a DNS leak test by using the command line: Another way to test your provider against DNS leaks is by querying Akamai. Simply run: nslookup whoami.akamai.net

This should link you to the IP address of your VPN provider, and not direct you to your local ISP allocated IP.

How can it affect you?

If any of your traffic, data or information should pass through the regular, unenclosed route, it may be interrupted by unauthorized parties such as your ISP or your DNS provider. This way, they would be able to view:

•  Any site you visit;
•  any files you download;
•  any service you use or more.

In addition to this, you won’t even know about it, unless you take a special test for DNS leaks.

How do I prevent DNS Leak?

•  Use a VPN service: One of the most popular ways to avoid a DNS leak is by using a VPN server.

A VPN (Virtual Private Network) service will enable you to have a protected and a private tunnel for any information to pass through and exist between your computer and the Internet. This way, you will be able to stay connected to your VPN server, and this will allow you to browse anonymously by concealing the origin of your IP.

While the main goal of VPN servers is to hide your IP address and encrypt your traffic or your data, not all VPN providers can ensure this. Many VPNs are in fact vulnerable to DNS leaks. Try to go through the VPN features available to users before choosing your next VPN provider, and ensure they can adequately protect you from any DNS leaks.

•  Use your own DNS resolving server: You can mount your own DNS resolver using any Domain Name System server However, same as in the “build your own VPN” solution, this must be done, where the ISP can ensure there will be no logging of your DNS requests.