Networking with native_posix board

This page describes how to set up a virtual network between a (Linux) host and a Zephyr application running in a native_posix board.

In this example, the Socket Echo Server sample application from the Zephyr source distribution is run in native_posix board. The Zephyr native_posix board instance is connected to a Linux host using a tuntap device which is modeled in Linux as an Ethernet network interface.


On the Linux Host, fetch the Zephyr net-tools project, which is located in a separate Git repository:

git clone

Basic Setup

For the steps below, you will need three terminal windows:

  • Terminal #1 is terminal window with net-tools being the current directory (cd net-tools)

  • Terminal #2 is your usual Zephyr development terminal, with the Zephyr environment initialized.

  • Terminal #3 is the console to the running Zephyr native_posix instance (optional).

Step 1 - Create Ethernet interface

Before starting native_posix with network emulation, a network interface should be created.

In terminal #1, type:


You can tweak the behavior of the script. See various options by running like this:

./ --help

Step 2 - Start app in native_posix board

Build and start the echo_server sample application.

In terminal #2, type:

west build -b native_posix samples/net/sockets/echo_server
west build -t run

Step 3 - Connect to console (optional)

The console window should be launched automatically when the Zephyr instance is started but if it does not show up, you can manually connect to the console. The native_posix board will print a string like this when it starts:

UART connected to pseudotty: /dev/pts/5

You can manually connect to it like this:

screen /dev/pts/5