# Where is the Io network interface used for?

**URL:** https://discuss.freedombox.org/t/where-is-the-io-network-interface-used-for/2786
**Category:** Uncategorized
**Created:** [November 5, 2023, 5:29pm UTC](https://discuss.freedombox.org/t/where-is-the-io-network-interface-used-for/2786 "2023-11-05T17:29:35Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![vincentvd](https://discuss.freedombox.org/letter_avatar_proxy/v4/letter/v/e9a140/32.png) [@vincentvd](https://discuss.freedombox.org/u/vincentvd)
#### Post date: [November 5, 2023, 5:29pm UTC](https://discuss.freedombox.org/t/where-is-the-io-network-interface-used-for/2786/1 "2023-11-05T17:29:35Z")

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I noticed the presence of the network interface “Io”. Has it always been present? I cannot remember that it was there before. I am also a bit curious where it is used for. Does somebody know that?

I didn’t install any new apps. My freedombox version is 23.19 on a RaspberryPi 4

 ![image](https://discuss.freedombox.org/uploads/default/original/2X/e/e790561619e6bb375ed0f7add7b15508a635fdb5.png)

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### Author: ![fefekrzr](https://discuss.freedombox.org/user_avatar/discuss.freedombox.org/fefekrzr/32/1686_2.png) [@fefekrzr](https://discuss.freedombox.org/u/fefekrzr)
#### Post date: [November 5, 2023, 11:20pm UTC](https://discuss.freedombox.org/t/where-is-the-io-network-interface-used-for/2786/2 "2023-11-05T23:20:20Z")

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Hello, the `lo` interface is the loopback interface.

_EDIT: Added another resource link. Answered questions in original post. EDIT 2: Added quote style to OP’s question. Rephrased my introduction._

> [@vincentvd](#):
>
> Has it always been present?

I believe it is present in most, if not all, UNIX-like operating systems.

> [@vincentvd](#):
>
> I am also a bit curious where it is used for. Does somebody know that?

Please read the resources below.

See below:

> **[Loopback | Virtual loopback interface](https://en.wikipedia.org/wiki/Loopback#Virtual_loopback_interface)**
>
> Implementations of the Internet protocol suite include a virtual network interface through which network applications can communicate when executing on the same machine. It is implemented entirely within the operating system's networking software and passes no packets to any network interface controller. Any traffic that a computer program sends to a loopback IP address is simply and immediately passed back up the network software stack as if it had been received from another device. Unix-like sy...

Also read:

> **[localhost](https://en.wikipedia.org/wiki/Localhost)**
>
> In computer networking, localhost is a hostname that refers to the current computer used to access it. The name localhost is reserved for loopback purposes.
> It is used to access the network services that are running on the host via the loopback network interface. Using the loopback interface bypasses any local network interface hardware.
> The local loopback mechanism may be used to run a network service on a host without requiring a physical network interface, or without making the service acce...

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### Author: ![vincentvd](https://discuss.freedombox.org/letter_avatar_proxy/v4/letter/v/e9a140/32.png) [@vincentvd](https://discuss.freedombox.org/u/vincentvd)
#### Post date: [November 24, 2023, 7:19pm UTC](https://discuss.freedombox.org/t/where-is-the-io-network-interface-used-for/2786/3 "2023-11-24T19:19:00Z")

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Thanks for the answer. Sorry, I thought I reacted but apparently not.

I know the localhost ip-adress, I have seen it in localhost software. I have never seen it in a list like this and I didn’t recall specifically enabling it. That confused me. But thanks for answering, it is clear now.