What is 127.0.0.1?
127.0.0.1 is an IP address which is also called loopback address or localhost. This IP address used by all computers but doesn’t used to communicate with other devices like other IP addresses. 127.0.0.1 IP (loopback address or localhost) address is used to communicate with the localhost to understand it in a simple way it is used to communicate with your own computer. Now you must be confused by reading the above line, so let’s first understand what local hosting is.
What is localhost?
In the terms of networking localhost is your own computer which means when you call localhost you are communicating with your own computer. To run your website on the internet you need a host just like that when you are making any website then you will need localhost so that you can test your website. Localhost allows you to test programs on your computer, without sending the data on the internet. Localhost is not only a virtual server but a domain name as well like .test, .example, or .invalid. It is a top-level domain that is reserved for documentation and testing purposes.
How does 127.0.0.1 (loopback) work?
TCP/IP sends the data packet containing the IP address of their recipient device. TCP/IP check every data packet before sending them to the physical network. When protocol detects 127.0.0.1 IP address in the data packet as recipients IP address, it sends back the data packet to receiving end of the TCP/IP stack.
To increase the security of networks, TCP/IP checks the data packets coming to routers or any other network gateways. If the data is coming from loopback IP addresses then TCP/IP discards that data packet. By doing this TCP/IP prevents a network attack from any person who can disguise their traffic a loopback address. Every computer has 127.0.0.1 referring back to its own server.
Where does localhost is used?
For Testing Purposes
The main use of localhost is the testing of programs on your computer. Before launching the website or any web application developer have to test the application actually working as hoped or not. For the applications that are going to communicate over the internet, developers have to check that it works fine once it has internet access.
Another advantage of using localhost is its speed. Sending a request over the internet can take up to 100 milliseconds while sending a ping to localhost only takes one millisecond.
To block website
Another advantage of localhost is that it allows you to block a website that you want to access. Localhost can prevent you from accessing a website that can contain a virus. When you enter a domain name to open a website, DNS (domain name system) covert it into IP address that is associated with that domain name. Every time you visit any website your computer saves a host file of every site you visit. These hosts file contains the domain name and IP addresses of every website that you have visited. You can open these hosts file and change the IP address of the website that you don’t want to access in the future into a 127.0.0.1 IP address. by doing so you will be redirected to your localhost from the site which host file you have changed.
With the localhost, you can check that everything working perfectly fine. You can simply open the command prompt of your computer and enter “ping localhost” or “ping 127.0.0.1” and then you will see how everything working on your network. You will be able to see data packets received, sent, or lost and how much time data transmission is taking. If there is any problem then it allows you to fix those problems.