Skip to main content

What Is 127.0.01 ?

24 June 2017 

Why Is Localhost’s IP Address 127.0.0.1? What Is Its Meaning?




Short Bytes: Ever wondered why 127.0.0.1 IP address is assigned to localhost? Why not some other IP address like 121.9.1.1 or anything else? The answer to this question lies in the fact that by 1981, 0 and 127 were the only reserved Class A networks. As 0 was used for pointing to a specific host, 127, the last network number, was left for loopback IP address or localhost.
You might have definitely heard of 127.0.0.1. You also might be knowing that 127.0.0.1 points to localhost. But, why is localhost‘s IP address 127.0.0.1–why not something else?
Before trying to answer that question, let me tell you a little bit about how does it work. This address is used to establish a connection to the same computer used by the end-user. When we deal with IPv6 address, it’s defined using the connotation of ::1. As IPv6 addresses take over, localhost will be more commonly know as 0:0:0:0:0:0:0:1.
How does 127.0.0.1 work? Why is it called so?
Very often developers use 127.0.0.1 to test their applications. When you try to establish a network connection to the 127.0.0.1 loopback address, it works in the same manner as making a connection with any remote device. However, it avoids connection to the local network interface hardware.
But, why does the localhost IP address starts with 127? Well, 127 is the last network number in a class A network. It has a subnet mask of 255.0.0.0. So, the first assignable address in the subnet is 127.0.0.1.
However, if you use any other numbers from the host portions, it should work fine and revert to 127.0.0.1. So, you can ping 127.1.0.1 if you like.
You might also ask why the last network number was chosen to implement this. Well, the earliest mention of 127 as loopback dates back to November 1986 RFC 990. And, by 1981, 0 and 127 were the only reserved Class A networks.
The class A network number 127 is assigned the “loopback” function, that is, a datagram sent by a higher level protocol to a network 127 address should loop back inside the host. No datagram “sent” to a network 127 address should ever appear on any network anywhere.

PROGRAMMING GIANT'S



Comments

Post a Comment

Popular posts from this blog

Babylon Health erases AI test event for its chatbot doctor

Babylon Health  has removed all traces of an AI test event it held last year to promote its chatbot doctor. The company’s  GP at Hand  app, which features the chatbot and can provide a video link with a doctor, was promoted by former UK digital secretary Matt Hancock and is backed by the NHS. Furthermore, Samsung  partnered  with Babylon Health last year to integrate the service with compatible Galaxy devices Babylon Health’s AI-powered chatbot aims to provide guidance on how a patient should proceed. The idea is to reduce the pressure on the health service from patients whose symptoms could be dealt with at home. In theory, it’s a great idea and will one day be how we access healthcare. However, as AI News has  reported  in the past, it’s currently not robust enough and has presented advice which could result in fatalities. Twitter user  ‘Dr Murphy’  has been highlighting the failures of GP at Hand over the pas...
Post a Comment
Read more

What is Deep Learning?

Deep Learning is a subfield of machine learning concerned with algorithms inspired by the structure and function of the brain called artificial neural networks. If you are just starting out in the field of deep learning or you had some experience with neural networks some time ago, you may be confused. I know I was confused initially and so were many of my colleagues and friends who learned and used neural networks in the 1990s and early 2000s. The leaders and experts in the field have ideas of what deep learning is and these specific and nuanced perspectives shed a lot of light on what deep learning is all about. In this post, you will discover exactly what deep learning is by hearing from a range of experts and leaders in the field. Let’s dive in. Deep Learning is Large Neural Networks Andrew Ng  from Coursera and Chief Scientist at Baidu Research formally founded  Google Brain  that eventually resulted in the productization of d...
Post a Comment
Read more

Different Types of Algorithms You Should Know Before Going To A Technical Interview!!

Khanday Jeelani | .NET Web Developer
Post a Comment
Read more