What is a loopback Ip, 127.0.0.1 ?

[pranav2794]

I found that my computer pings all the IP addresses that starts with 127.0.0.1 to 127.0.0.255, Till now I saw only those things getting pinged which have their LAN cards, Now from where so much of cards arrived in my LAN ( 255 LAN cards ! ).

I heard about this as a loopback, which I am not sure of, tell me about this.

I have also heard that this IP is very much dangerous for script kiddies, like if you give them this IP then it will damage their own host from which they are attacking.........
So I just wanna know what is all this in detail !

[caracarn001]

loopback address
To keep things simple: the loopback address refers to your own computer. If a skiddie attacks this address, he's basically attacking himself.

[pranav2794]

My computer is only one but the ping requests get reply from all the 127.0.0.1 to 127.0.0.255. I have only one computer not 255 !

[epifany]

That's because 127.0.0.1 is a loopback address. 127/8 is the range of addresses that are reserved for loopback. This can make it even more fun to mess with people because a lot don't realize that 127.254.195.71 will also point to the localhost.

Loopback is mostly just for testing the functionality of IP on your computer, but it has some other uses; like accessing services that are running on your own machine.

Check out this list of other special-use IP addresses: http://tools.ietf.org/html/rfc3330

[pranav2794]

every such IP address like 127.211.200.45 is same as 127.0.0.1 and it will first loopback to 127.0.0.1 which is our host.
which means only 127.0.0.1 is my host and any other 127.0.0.0/8 will first become 127.0.0.1
am i right,. ?

[epifany]

Almost.

Various loopback addresses don't become, or turn in to, the 127.0.0.1 address. All of them simply point to the same place. There's really nothing significant about 127.0.0.1, besides being the most popular loopback address to use.

[ampakine]

The hostname for it is localhost.