Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

Why is Microsoft Loopback interface called _loopback_ inteface?

RFC3330 states that a loopback interface is an interface with an IP address in the 127.0.0.0/8 address range.

Yet, when I enter the 127.x.x.x address in Microsoft Loopback TCP/IP settings, Windows returns an error.

What is its purpose?

share|improve this question
    
I've asked the question because I'm confused what the 'loopback' word actually means. As I understand from the sysadmin1138 s response, the word has many meanings depending on the context the word is used in. I.e. I haven't thought about the IPX protocol. –  colemik Dec 18 '11 at 23:37
    
Fair enough. I have update the question to make it less.. ranty –  Mark Henderson Dec 18 '11 at 23:58
    
Loopback adapter? thinkgeek.com/gadgets/tools/6c20. You cannot assign any IP addresses to that. –  Zoredache Dec 19 '11 at 2:40
    
One example of real-world use of the Microsoft Loopback Adapter is to establish a virtual network between a virtual machine and the host, without allowing the virtual machine access to the physical network. –  Harry Johnston Dec 26 '11 at 3:53
    
You're confusing loopback interface with loopback address. They both do similar things, but are not the same thing, as others have pointed out. –  John Homer Jan 10 '13 at 20:41

1 Answer 1

up vote 8 down vote accepted

Because Microsoft is treating it like a loopback physical interface. On _loopback_ you can assign any protocol stack Windows works with, including IPX (up to certain Windows versions) which isn't a TCP/IP protocol at all. The TCP/IP concept of a loopback interfacce is a logical concept, and 127.0.0.0/8 addresses apply to the local machine entirely; I don't believe you can explicitly bind them on any Windows adapter.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.