We can all agree, google.com is way easier to remember than 172.217.15.78; and yet, both go to the same website. Why do numerical addresses even exist if we do not use them?
In the 1970s and 80s, the internet was nothing like what we think of today. It was mostly used by universities and the military to share notes and research amongst themselves. Due to the small amount of computers connected, only a small amount of addresses were needed. These early machines were connected by what is called ARPAnet.
However, in 1983 everything changed with the introduction of the TCP/IP model. No longer were we constricted to only a few hundred addresses, we now had over 4 billion! However, these billions of new addresses presented a problem, how do we keep track of them all?
DNS
Domain Name System (DNS) is essentially the address book for the internet. We as humans remember words or domains, therefore, google.com is easier for us to use. However, a computer and web browser communicate using IP addresses, 172.217.15.78. DNS takes the human readable domain and translates it to its machine readable address.
A Brief History
Before 1983, a HOSTS file, hosts.txt, was needed to communicate with another machine over APRAnet. The hosts.txt was a list of known computers and their addresses. The system worked great when there was a small amount of addresses, but now we have over 4 billion! Luckily for us, Paul Mockapetris “proposed a distributed and dynamic naming system, the first iteration of the DNS we have today.”1Internet Hall of Fame
“DNS created easily identifiable names for IP addresses”
Internet Hall of Fame
Instead of your computer needing to know where every other computer was on the internet, it could just ask for the information. “DNS created easily identifiable names for IP addresses, making the Internet far more accessible for everyday use.”2Internet Hall of Fame. This was a huge step towards the internet we know today.
How does DNS Work?
DNS resolution is the process of taking a domain (google.com) and translating it to it’s IP address (172.217.15.78). And since every computer on the internet needs a unique address, it happens a lot. The process takes place in the background every time your computer needs to communicate online. If a computer does not know the address of a website, it will reach out to a DNS server to learn the address first.
DNS Caching
Many web browsers and operating systems (os) have the ability to cache already resolved addresses to use in the future. Before reaching out to a DNS server, the web browser checks the browser cache and then the os cache for an answer. If neither cache has the information, a query is sent to an external DNS server. “The closer the DNS caching occurs to the web browser, the fewer processing steps must be taken in order to check the cache and make the correct requests to an IP address”3Cloudflare, thus making the lookup faster. Caching is a great way to speed up your most used sites, and luckily it is enabled by default.
DNS Security
Have you ever wondered how the ads on the side of web pages can show you targeted ads? Well, it could be from your DNS queries. DNS traditionally runs over unencrypted channels, since no personal information is sent with the request. Because of this, your internet service provider (ISP) can see every website your computer goes to, even if the website itself is secure. “Some providers even sell this data, or use it to target you with ads.”4Cloudflare DNS
“Some providers even sell this data, or use it to target you with ads.”
Cloudflare
DNS over TLS is the secure and encrypted form of standard DNS and is generally preferred. Using a secure DNS protects your information from snooping eyes and can keep your data protected with encryption. Google and Cloudflare both offer free DNS over TLS options and are great choices. There are also numerous paid programs as well; however, the free ones work just as well, if not better.
DNS Failures
By default, a DNS server is provided to you automatically, generally by your internet service provider (ISP). Typically the ISP controls and maintains the server to ensure it is running properly. While not common, a DNS server can fail and cause some users to appear as if they are offline. When a failure occurs the only way to reach a website is by the IP address of the server, which is impractical, or to change your DNS server.
Changing your DNS can be done on Windows, OS X, linux, and most routers have a setting for it. If you are curious about how to change your DNS, Google has written up a good guide to do so. Feel free to follow the guide even if you want to use a different DNS provider other than Google. Just remember to use those DNS IP addresses instead of Google’s. However, do be careful poking around in the settings. A mistyped DNS server, or other wrong settings, can stop internet traffic.
The Future
DNS has changed with computers, and will continue to change as new innovations are made. It has become an integral part of the internet and I do not see it going away. However, we can expect see new and improved versions, especially when it comes to security and speed.