How Internet Works
URL
When you want to visit a website using a web browser, the following happens sequentially.
- You open a web browser, type the website address (known as URL) and press enter.
- The website is hosted on a webserver. That webserver receives the request to provide webpage to you.
- The webserver provides the latest webpage to your browser.
- You get the webpage of the website you wanted.
In the above example, we need to observe the following key points –
- Web browser is a type of web application, residing on your computer or mobile set.
- Website address, also known as URL or Universal Resource Locator, is the address of the webpage residing on a webserver.
- Web server is another type of web application.
- Communication happens between two applications here, web browser and web server.
- For two applications to communicate, the first requirement is to have right address of each application.
- URL is the address of the website residing on webserver application.
The key point to note –
- Communication happens between two application
- For two applications to communicate, both have same type of addresses.
Applications are installed or reside on machines such as computers or mobile phones.
When two applications communicate with each other, they do it via the two machines on which they reside. Thus, a complete address of an application includes the address of the machine also.
The internet address of a machine is known as an IP address or Internet Protocol Address.
Coming back to the URL now which you typed to get a website, the URL connected your browser with the webserver to get the webpage.
The webserver is another application installed on a machine. Usually, such machines which have web servers are called Server Machines.
The URL which is the address of the webserver application indirectly includes the IP address of the server machine also. This is done via mapping URL to IP address by DNS or Domain Name Server. We would learn about it later on in this course.
The IP address of a machine can be configured using a utility inside the operating system. Thus, this is actually the internet address of the operating system, we can say, which resides on the computer machine.
- To know the IP address of your machine, you can type ipconfig on the command prompt, in case you have windows operating system.
- To know if a URL exists or not, you can type PING on command prompt and then type the URL and enter. If URL is alive, you would get a response where IP address related to the URL will be mentioned.
The machine has another address as a physical address which is usually hardcoded on the network card installed on the motherboard. The physical address is hardcoded and cannot be changed normally.
This physical address is unique across the globe for any machine which means that no two machines in the world can have the same physical address.
IP address
Applications are installed or reside on machines such as computers or mobile phones.
When two applications communicate with each other, they do it via the two machines on which they reside. Thus, a complete address of an application includes the address of the machine also.
The internet address of a machine is known as an IP address or Internet Protocol Address.
Coming back to the URL now which you typed to get a website, the URL connected your browser with the webserver to get the webpage.
The webserver is another application installed on a machine. Usually, such machines which have web servers are called Server Machines.
The URL which is the address of the webserver application indirectly includes the IP address of the server machine also. This is done via mapping URL to IP address by DNS or Domain Name Server. We would learn about it later on in this course.
The IP address of a machine can be configured using a utility inside the operating system. Thus, this is actually the internet address of the operating system, we can say, which resides on the computer machine.
- To know the IP address of your machine, you can type ipconfig on the command prompt, in case you have windows operating system.
- To know if a URL exists or not, you can type PING on command prompt and then type the URL and enter. If URL is alive, you would get a response where IP address related to the URL will be mentioned.
The machine has another address as a physical address which is usually hardcoded on the network card installed on the motherboard. The physical address is hardcoded and cannot be changed normally.
This physical address is unique across the globe for any machine which means that no two machines in the world can have the same physical address.
Network Gateway & DNS
When you type the URL on the web browser of your laptop at home, it gets the webpage of the URL you typed. In this process, your machine at home contacts the webserver machine on the internet.
If you find the IP address of your machine at home, it may start with 192.168.X.X mostly. However, if you get the IP address of www.google.com for example, it would be mostly starting like 172.217.X.X
The network at home is usually a private network. Whereas the network on the internet is a public network. Thus, when your machine from home contacts the webserver via the internet, it is an interaction between a private network and a public network.
Your machine at home is connected to a wi-fi gateway mostly. This gateway connects your private network to the internet.
Within your private network, you may also have a TV, a Printer, and a few cell phones using the internet service provided by your service provider via wi-fi gateway.
All the machines inside a private network such as your home network have IP addresses as per private network configuration settings. These machines can communicate with the internet only using the gateway which has two interfaces, one for the private network and another for the public network.
When you type a URL on the web browser, it is converted into an IP address. This is done by a DNS or Domain Name Server. The public IP address of a DNS is configured in the wi-fi gateway.
There are many DNS on the internet and your machine connects to one of them which is configured in the gateway.
A DNS Client is called DNS Resolver.
