DNS and propagations

Hmmm... what is getting propagated?

So what is a DNS?

DNS stands for "Domain Name Server". Think of it like a dictionary. Remember that you visit a website by typing its name in the address bar? Such as google.com? Well, the Internet is quite a primitive beast. It really does not understand that "address" -- so it looks up this specialized register or dictionary; and gets the IP address of it.

Oh. More jargon. What is an IP address?

IP address are 4 numbers (usually, there is another format but let us not confuse you) separated by dots. Think of it like a specialized address. Look at the four numbers as: CityNo/StreetNo/BuildingNo/ApartmentNo.... Not exactly but ... its an analogy. You think along hierarchically to zero-in onto a physical address by processing each of those numbers one after another. That is also (simplistically) what these DNS allows computers to do too, in order for a browser to reach the website of a domain. So the Internet understands this 4 number-separated-by-dots IP address, and can locate your website once you gave it your website address. Why? Because the "dictionary" in the DNS translated the name of your website to such an IP address.

Let's confuse you a bit

It turns out that some website address can be located by other means too -- the DNS does a lot of other clever such "dictionary translations". For example; when hosting a website our system, you actually do not have to specify the IP address of your website in the dictionary. There are other magical things happening in the background which precisely locates your website; and you will never have to worry if by some chance the pages displayed in your website is the wrong one. If you pinned (pinning is explained in a different topic) those files; those would be exactly the files that would be in your website!

Propagation. What does that term mean?

The Internet is a vast network. Kind of a gigantic fishing net floating high above in the cyberspace. Each intersection of the twines of that net can be potentially where some "server" or the other is located. A server is special type of computer that is used to make websites work. To confuse you further sometimes the term "server" also means the special web hosting software that runs on that machine, which actually does the work. So the DNS is also a "server" (The last "S" in that abbreviation stands for server)

There is ONE main DNS server where such Internet settings of your website are created and managed. That main server is called THE "nameserver" -- explained in another chapter.

Well, if your site settings are stored only one DNS then people who want to visit your website would have to travel down those twines, to reach that specific DNS, right? As the world is very large and since these servers (hardware) are located in different cities, there will be a time lag from one end of the world to the server(hardware) located at another end. To avoid that time lag; the configuration of your DNS settings are actually stored across a huge number of other DNS server spread right across the Internet. These DNS severs communicate at a regular time interval (set by "timetolive" or "ttl") parameter to do the synchronization with your site's main name-servers. This works quite well most of the time. Sometimes when a particular server may miss that sync, and that particular DNS server may not have the correct information -- it would surely get synchronized later. But exactly when later? Cannot say -- that is how the Internet works. It gets the job done, but sometimes you only have a rough idea of the time taken. This is one such situation. So, when someone wants to visit your website, the settings are picked up from a DNS that happens to be close by in the network of computers.

This has one important downside: When you make changes to your DNS settings, the changes that you had made can take some time to spread across to the other slave DNS servers across the Internet. As explained earlier, a few server may not sync too well; and so may have the older information.

That time it take to sync and reconfigure your site settings on other servers is what is called "propagation" time. Possibly if they had called it "spreading" time, it would have been more confusing.

In the DeSec.io DNS system (which is what we have integrated) the "ttl" for these DNS Settings is 1 hour (3600 seconds). So on an average the largest sync time is one hour for your settings to take affect, but because of delays in synchronization it can occasionally take a few hours.

OR to put it simply: Once you use BushFire to start a website; there could be (occasionally, and hopefully rarely) some situations that your website can actually be seen by the world after a few hours, and not the expected few minutes.