Loopback ip address?

[nettizen]

What is this so called loopback ip address and what is it used for? My Hijackthis list this as a BHO. HKCU\Software\Microsoft\Windows\CurrentVersion\Int ernet Settings,ProxyServer = 127.0.0.1. Should I fix it? is it needed? Please help. Here is an explanation of the ip range "127" but I dont understand it: 127.0.0.0/8 - This block is assigned for use as the Internet host
loopback address. A datagram sent by a higher level protocol to an
address anywhere within this block should loop back inside the host.
This is ordinarily implemented using only 127.0.0.1/32 for loopback,
but no addresses within this block should ever appear on any network
anywhere [RFC1700, page 5].

[SpookyEddy]

Quote:

The Internet protocol (IP) specifies a loopback network. Under IPv4, this has the CIDR address of 127.0.0.0/8. Most IP implementations support a loopback interface, which represents the loopback facility. Any traffic that a computer program sends on the loopback network is addressed to the same computer. The most commonly used IP address on the loopback network is 127.0.0.1 for IPv4 and ::1 for IPv6. The standard domain name for this address is localhost.

For the full article... http://en.wikipedia.org/wiki/Loopback

Regards

ed

[paul9]

the most common uses i know of for the loopback address are:
1. ping the address to help determine whether your networking is in a mostly working state.
2. point 'nuisance' or other unwanted internet sites to the loopback address in the hosts file. this stops the computer from finding these unwanted sites.

[SpookyEddy]

Quote:

1. ping the address to help determine whether your networking is in a mostly working state.

You can ping loopback all day without even having a network card in the box. How does having a working loopback tell you anything about the state of your network?

Regards

ed

[muno]

It should tell the state of tcpip stack If loopback ping fails, there's something badly wrong with it

[paul9]

not the card, eddy, but the software components of the networking system. that was the reference to mostly working, as opposed to fully working. sorry if i caused confusion.

[kwebb]

Quote:

Originally Posted by SpookyEddy

You can ping loopback all day without even having a network card in the box. How does having a working loopback tell you anything about the state of your network?

Regards

ed

NIC's dont' have much of anything to do with the loopback addy.

Loopback is predominantly a functionality tool, not a connectivity tool.

Localhost. Start a webserver on your box with a standard start page, index.htm or whatever, then open a browser and type localhost/index.htm. In a very general description, it's your computers address.

[SpookyEddy]

Yeah I suppose its useful to see if you have some kind of functional network stack.

Regards

ed