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ifconfig shows only one loopback address and that it is assigned to network interface lo.

ping can receive packets back, even though is not assigned to a (virtual) network interface.

Does a loop back IP address not need to be assigned to a network interface, in order to communicate with?

If no, why is assigned to a virtual network interface lo, if it doesn't need to be assigned in order to work? Some said at https://unix.stackexchange.com/questions/507980/why-is-some-virtual-network-interface-assigned-private-ip-address-while-some-is#comment938403_507987

lo gets an IP address assigned to it so that packets sent from it have a source IP address

What does that mean?


marked as duplicate by Ron Maupin Mar 24 at 3:04

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • How a particular host OS handles this is off-topic here. The entire network loops back inside the host. It is like assigning a /8 network address to a Cisco router loopback interface; everything sent to that network will hit the loopback, even if it is not the specific address assigned to the loopback interface. The specific ` address is assigned to th interface, but the interface contains the entire network because the network is only attached to the host. – Ron Maupin Mar 24 at 3:08
  • By the way, you are asking a lot of questions, for which you have received many good answers, but you have accepted answers on relatively few of your questions. People expect to be recognized for their time and answers, and you may find fewer people willing to answer your questions if you do not acknowledge their answers with acceptance (it is simply courteous). If the answers are lacking, you should comment to the answers to clarify. – Ron Maupin Mar 24 at 3:16
  • (1) If I don't really understand yet and pretend to accept a reply, will that make people more willing to answer my questions? (2) Some users on Unix.SE claimed my questions not OS-specific (all OSes have the same concepts), so I tried my luck here – Tim Mar 24 at 11:50
  • If you still do not understand an answer, you should use comments to solicit more information. As far as I can tell, each of your questions do have at least one correct answer. Part of the problem with your questions is that you are skipping around in subjects, not getting a good understanding of one subject before moving on to another subject that depends on the first subject. I have seen this with other users in the past. For example, your question about multiple MAC addresses shows that you do not fully grasp what each network layer does, and you should first understand that. – Ron Maupin Mar 24 at 17:46
  • You also have enough reputation that you can take off-topic questions like this one to Network Engineering Chat. Questions there should not be on-topic for the main Q/A site. – Ron Maupin Mar 24 at 18:35

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