Why localhost is 127.0.0.1

Add a comment. Earliest mention I can find regarding 's assignment as loopback is November RFC authored by Reynolds and Postel: The address zero is to be interpreted as meaning "this", as in "this network". For example, the address 0. Even as early as September RFC , 0 and were already reserved: Community Bot 1. Joseph Bui Joseph Bui 3 3 silver badges 4 4 bronze badges. Note that I used "words" because old machines back then had unusual word sizes, but they often still used 8 bit arithmetic.

For an , I would have said "bytes. In the end: 0, and could all be checked for with an one, fastest, instruction. Dario Fumagalli Dario Fumagalli 2 2 silver badges 4 4 bronze badges. Great answer. This is really the clearest and most sensible explanation. Actually, back when IP was designed and some of the early groundwork for it was laid down, working with data in integer multiples of 8 bits wasn't a given. Many architectures at that time had registers and word sizes in multiples of 12 or 18 bits, for example.

This is one reason why octal was so popular at the time; 18 bits can be represented as exactly 6 octal digits with no loss and no waste; 12 bits is 4 octal digits. Microcomputers typically worked in 8-bit quantities, but it was only much later that microcomputers started being regularly connected especially directly to the Internet. How come it's obvious again? I believe they just chose something simple. Again, all "1"s is reserved, so one zero was added : — kolypto.

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How to Login to your Hotmail Account. How to Download Twitter Videos. Spotify Web Player Not Working? It's very important to know that it will not go through network card when using localhost while it will when using Generally speaking, localhost is a better option when configuring local testing environment.

Sometimes some connection is working with localhost but is not working with Furthermore, when using localhost to access resource, it is accessed with the local user privileges, while it will use the network user privileges when using Toggle navigation. Basically, when you call by server name, it is converted to original IP. But it would be difficult to memorize an IP, for this reason the domain name was created. The Mask The Mask Don Viegues - what you say is contradicted to the other answers in this thread.

Can you elaborate? Yes, I will copy and paste other comment of mine: The main difference is that the connection can be made via Unix Domain Socket, as stated here: stackoverflow. Other applications will likely still lookup localhost.

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