Most people use the internet without knowing how it really works. The Internet relies heavily on a Domain Name System (DNS). DNS is a comprehensive translation system that is employed to search the internet. It is a database of network names and IP addresses. For this reason, it is often referred to as “the phone book of the internet.”
Without this system, you would be left dealing with ones and zeroes. While the concept might seem basic, it is the cornerstone in the functionality of the internet.
Below are seven interesting facts about DNS that you should know.
1. The History of DNS
It is imperative for internet users of today to be aware of the evolution of DNS. This system is more than 30 years old. The concept was initially utilized to help with increasing email communication on the ARPANET.
Before DNS, a public system could only be identified by its hostname. The addresses tied to all these hostnames were maintained in a large file (named hosts.txt). This system was extremely difficult to manage following the growth of computer networks in the 1970s and 1980s.
DNS was an expansion of this single-level naming system to the multi-level system, through the addition of support domains. This means that one or more names were appended to the hostname, with a dot (.) separating each additional name.
2. DNS Leaks are Common
A DNS leaks refer to an instance whereby a user’s IP address becomes visible to the public domain after they have taken steps to conceal the IP. Many internet users today utilize a number of tools to hide their IP addresses from their Internet Service Providers (ISPs) as well as potentially malicious actors on the internet.
Most of these tools operate by channeling Internet traffic over a wide network of computers. When the traffic fails to reroute via the protected channel and moves through the ISP, a DNS leak has occurred. Fortunately, this can be prevented by following this step-by-step guide.
3. Functions of DNS
In the simplest form, the DNS is a database tasked with maintaining the names of websites and linking them to IP addresses consisting of a number pattern. DNS also helps locate IP addresses to specific website names and then stores this information. This process is known as record maintenance.
Its second function is to distribute the DNS over a large network of connections.This system can also hold a vast library of records.
DNS is a database that can easily be shared since each server holds a small portion of IP addresseswith hostname mapping details. The collection of IP address to hostname mapping is referred to as the namespace.
When a user looks up a name in the DNS, they have to check the high-level database which directs the client on how to check the DNS server host. The system then specifies queries that can be addressed by the client via the hostname provided by the DNS server. This process continues until the user locates the correct server hosting the required DNS.
The records maintained by the DNS can be useful for other services and can aid applications. DNS may seem complicated, but only because other processes such as email rely on it to function.
4. DNS Structure
DNS architecture is based on a hierarchical distributed database governed by a set of protocols. The names in the DNS form a hierarchical tree structure referred to as the domain namespace. These names are tied to individual labels, which are then divided by dots.
A domain name that is fully qualified will be unique enough to be identifiable through the host’s position on the DNS tree. A DNS database is often divided into a number of zones. Each zone bears a portion of the DNS database. They house the resource records of the names that comprise the namespace.
As such, each zone is part of a particular domain name, which is called its root. A zone contains all the data regarding the names and ends in its domain root name. There are standard categories utilized to describe domain names and functions:
· Root domains: These are found at the highest level of DNS hierarchy, and they represent an unnamed level. Root domains point to an exact location on the DNS tree.
· Top level domains: These are used to describe an organization, region or country.
· Second level domains: These are variable length names assigned to appropriate top-level domains depending on the geographical location or organization.
· Third level/subdomains: These are used to describe organizations created from the second level domain names. These include terms that are added to enhance the hierarchical organization.
5. DNS Hijacking is Possible
Reports of hackers hijacking DNS systems pop up in the media from time to time. DNS hijacking is a cyber attack whereby the hacker manages to gain access to the DNS server data of a target website. The hacker then proceeds to modify these records in order to redirect the site’s visitors to another site that they control.
When an internet user visits a site that has been hijacked, the DNS communicates with their browser to request information from the hacker’s bogus site.
It is worth noting that cyber attackers do not have to compromise the DNS itself to execute such attacks. They only have to compromise the service hosting the domain.
They often accomplish this by posing as web administrators. This is exactly what happened to the whistleblowing release site WikiLeaks earlier this year when the website was taken over by a group of hackers. DNS hijacking can be particularly difficult to guard against.
6. DNS has Grown to 700 Top Level Domains (TLDs)
The internet is now home to more than 700 top-level domains (TLDs). A TLD refers to one domain on the highest level of the internet’s hierarchical DNS. It is the final label of a fully qualified domain name.
Some of these TLDs possess some particularly odd names such as .soy and .rocks. The allocation of top-level domains is controlled by the Internet Corporation for Assigned Names and Numbers (ICANN), a nonprofit governing body.
However, only six top-level domains were defined by DNS when it was first implemented back in the 1980s. These included .com, .gov, .edu, .net, .org and .mil. In 2011, there was a great expansion in top-level domain name choices. This served to classify websites according to their purposes for convenience.
7. Works in Forward & Reverse
A large percentage of requests to the DNS aim to convert the hostnames of site and internet servers to IP addresses. These are referred to as forward DNS lookups or mapping. DNS also operates in the reverse direction. The system can translate IP addresses to hostnames. These requests are referred to as reverse DNS lookups or mapping.
Reverse DNS lookups are far less common. However, they serve as a very useful function for network administrators as they help with troubleshooting. A mail server can also utilize reverse mapping to conduct sanity checks after another mail server connects to it. The IP address components are reversed during reverse mapping as well.
DNS gets taken for granted largely because it is not something that people encounter regularly when using the internet. Yet, it is the reason the internet has existed as is for more than two decades.
As such, it is important for internet users to appreciate the role this system plays in ensuring ease of use.