How domains, IP addresses and servers works

I’m going to walk you through how part of the internet works as simply as possible.


How does it happen, that someone type and then see some web pages? Where this come from?

A little background. On internet we have IP addresses to give every computer it’s specific name. Because we don’t like these awful numbers (like, we have nicknames for them - domains. For example - you know that when you type, you get to google page. But that happens even if you type: In first example it does this:

  1. It takes name
  2. Goes to world data bank of domains and their appropriate IP addresses
  3. Find out which IP address belongs to this name
  4. Get you to this IP address

You can buy your own domain and then redirect it to your IP address. Redirecting is made by adding A record. This is usually done on their administration website. Then, after few minutes (or hours), it is registered in this world data bank.

There is also free alternative, for example It’s not second-level domain (the one which is right before .com, .eu...) , but third-level (e.g., ...). You can use it in our example - just register there and choose your domain name (e.g. Then you add name (that’s prefix before - in my case mojepks) and destination - that’s your public IP address.

Public IP

What is public IP address? It means that this address is one on the whole internet - it points to one specific place on the world.

if you are connected to some network, for example to your home router, you have one internal network. Usually it’s something like But this is not an address people can see you from the internet. It’s just the internal one. On Linux you can find it by typing:

ip addr

to find your public IP address, you can find it e.g. here. But this address is most probably isn’t of your PC, but of the router you have. And not even that - it might be and IP address of some other node to which your router is connected to. To find this out is best to ask your administrator or IPS (a company, which is offering you and internet).

It means, unfortunately, that not every one has it’s own “public” IP address and even worse, it can change! And that is not what you want - then you should have had to change it every time your IP get changed. You have to ask to your IPS if your address is “static” or “dynamic”. My IPS (UPC CZ) told me that my is “dynamic”. But after a little research I found out that it means that my IP address can theoretically change. In real, it is same for few years now :) . It is relatively common, so maybe you are lucky.

If you don’t want to buy “first level domains” (the one which are just and second level is enough (like, then you can take a look on getfreedomain. It will serve good for our purposes.