What is a localhost?

In computer networks, whenever we need some resources, we send a request to the server machine from our local client machine using the IP address. The server machine can be remote or locally installed on your local machine. So, in all those situations when we are using our local machines to perform the task of a server, we are using the localhost.

In this blog, we will learn what is localhost and the various applications of localhost.


Localhost is the local machine that provides the functionalities of a server. We need a local IP address that is ‘’ to connect to our local machine and use its functionalities. When we are connected to our personal home network, the IP address of our localhost is ‘’. When connected on the internet our localhost may have different IP addresses. This IP address is dynamically assigned by the Internet Service Provider(ISP). We can connect and communicate with our localhost using these IP addresses. It also enables us to use the files and resources of our local machine. It acts as a virtual server, whenever you are connected to the localhost, you are talking to your own computer. In the below-mentioned picture you can see, we are using the localhost to display the web contents.

Actually, the localhost is a hostname that refers to the same computer or machine. We need a ‘lookback’ technique to connect to the localhost. In lookback, the information sent to the network by the client machine is routed back to the local machine. This lookback address is mainly used to establish an IP connection with our local machine.

The localhost behaves as a local server that allows you to host a program or application on the local machine by providing a network interface without having the physical networking resources. It is the place where your programs or applications are residing. In other words, the localhost can be used with the help of lookback addresses in order to use the network services by connecting other host computers or web servers like Apache web server, etc.

Localhost can be used for the following applications:

In Development: The application developers can check whether their application is executing fine or not using the localhost. They do not need to own all the network resources for running the application, they just need some web servers to access the localhost as the server.

In Testing: The testers can use the localhost for testing the applications. They can check whether the application is meeting the business demands or not before deploying the application on the server.

Running a Speed Test: We can send a ping request using the lookback address for checking the network speed. The result of the ping request includes the number of data packets sent, received, lost, and the time taken in round-trip data transmission.

Blocking Websites: Localhost can also block malicious websites. Actually, there is a host file in the local machine, which contains the mapping of IP address and the domain names. If we assign the localhost domain name to some malicious IP address. It will safeguard us from opening these malicious websites.

This is all about the localhost and its application in computer networks. Hope you learned something new today. That's it for this blog.

Do share this blog with your friends to spread the knowledge. Visit our YouTube channel for more content. You can read more blogs from here .

Keep Learning :)

Team AfterAcademy!