November 2023
Updated July 2024
The INTERNET is actually an infrastructure made up of (originally) copper cables most of which are laid underground but some are overhead and some are even laid on the sea bed! Most of the cables have now been replaced by “optical fibre” cables. The modern internet also makes use of electronic boxes called routers and switches.
To enable this infrastructure to work in the modern world, even before fibre cables were used, we needed a “system” that made the Internet work. In 1983, Paul Mockapetris came up with DNS (Domain Name System).
All computers / devices that are part of a “Network” need to have a unique “IP address” otherwise they can’t do the networking thing. When the WWW (World Wide Web) was invented by Tim Berners Lee in 1989, DNS became a neccessity.
DNS converts “human friendly” Web addresses to IP addresses. So when you use a web bowser and enter a web address (a.k.a. an URL) e.g. pcjudo.co.uk, you will arrive at my website. My web site is hosted on a “Web Server” and currently has an IP Address of 185.199.221.29. bbc.co.uk has an IP address of 151.101.0.81. Facebook.com has an IP address of 157.240.225.35. Google.co.uk has an IP address of 142.250.187.195.
Entering a load of numbers is not very friendly. Those IP addresses above are the old IPv4 addresses which use 32 bits of info in “Dotted Quad” notation, the new ish IP Addresses are IPv6 and use 128 bits of info. The IPv6 address for Google.co.uk is 2a00:1450:4009:81f::2003. Fortunately IPv4 addresses are still (currently) used alongside of IPv6.
DNS is also used in networking in general. If you have a few PCs on your network (LAN), each PC will have a DNS cache that stores the IP Address of other PCs you have connected to. In this case it stores the “hostname” along with the IP address. The DNS cache also stores info on web sites that the your PC connects to make quicker connections without having to go through the DNS query.
You can see the contents of the cache on a Windows PC by opening a Command Window (as admin) and type in “ipconfig /displaydns”.
The DNS system is the magic that makes the WWW work by storing IP addresses along with the (human friendly) Web Address. You can think of this as an electronic phonebook. There are several types of DNS server but you don’t really need to know this 🙂
DNS servers are dynamic in that they are updated automatically with any changes. This means that if a new website is created, the IP Address is added to the DNS database. Sometimes the IP address of a web site changes, any changes to the IP Address or Web site name are amended automatically. There are 100s of DNS servers that are accessed by the “Global Internet” and they all “talk” to each other, any changes are replicated to all DNS servers and this can take from about 20 mins to a few hours and this is done automatically. It’s not really magic but it looks that way 🙂
If you are a typical computer / internet user, you don’t really need to know any of the above, in the same way that you don’t need to how your car works but I think it is important that we remember the brilliant people who are responsible for enabling us to use our modern electronic world.
If you want to read more about “what is DNS“, this link will take you to Cloudflare.
If you want to know more about DNS servers, this link will take you to Cloudflare.
We take DNS for granted but without it our “Global Internet” wouldn’t work in a timely fashion. When DNS is setup correctly, you can enter a web address into your (web) browser and it will take you there. There should be no need to enter “http /https” or “www” before the “domain name” if the DNS settings have ben set up correctly. e.g. https://www.pcjudo.co.uk is the full web address of my site but just entering “pcjudo.co.uk” will take you to my site.