This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

Sample TELNET console application


This application will setup IPv4/IPv6 addresses on the default network interface. The telnet console service is started transparently by the kernel, along with the shell and two shell modules: net and kernel. Once up and running, you can connect to the target over the network, using a telnet client.


Building and Running

QEMU x86

These are instructions for how to use this sample application using QEMU on a Linux host connected to a network with DHCP service.

To use QEMU for testing, follow the Networking with QEMU guide.

Run Zephyr samples/net/telnet application in QEMU:

west build -b qemu_x86 samples/net/telnet
west build -t run

Once started, you should see you IP address details for example:

[Setup] [INF] main: Starting Telnet sample
[Setup] [INF] setup_ipv4: IPv4 address:
[Setup] [INF] setup_ipv6: IPv6 address: 2001:db8::1

At this point, your QEMU guest is up and running. Connect to the telnet console from your linux host this way:

$ telnet
Telnet escape character is '^]'.
Connected to
Escape character is '^]'.

Now type enter, the shell prompt will appear and you can enter commands, for example help.

Freedom-K64F Board

These are instructions for how to use this sample application running on a Freedom-K64F board. Unlike running it on QEMU, Freedom-K64F board network configuration for IPv4 will rely on DHCPv4. You cad modify the prj_frdm_k64f.conf to set static IPv4 addresses if it is really needed.

For detailed instructions about building, flashing and using the serial console logs, follow the Freedom-K64F board documentation section.

Connect ethernet cable from Freedom-K64F board to a local network providing IPv4 address configuration via DHCPv4. Creating your own DHCP server on a local network is not in the scope of this README.

Build Zephyr samples/net/telnet application:

west build -b frdm_k64f samples/net/telnet

Flash the resulting Zephyr binary following the Freedom-K64F board documentation noted above.

From your host computer, open a serial console to your board:

$ sudo screen /dev/ttyACM0 115200

Plug the Ethernet cable to the Freedom-K64F board. Reset the board, you should see first on the console:

[dev/eth_mcux] [INF] eth_0_init: Enabled 100M full-duplex mode.
[dev/eth_mcux] [DBG] eth_0_init: MAC 00:04:9f:69:c7:36
shell> [Setup] [INF] main: Starting Telnet sample
[Setup] [INF] setup_dhcpv4: Running dhcpv4 client...
[Setup] [INF] setup_ipv6: IPv6 address: 2001:db8::1

And if the DHCPv4 client succeeds, you will soon see something like:

[Setup] [INF] ipv4_addr_add_handler: IPv4 address:
[Setup] [INF] ipv4_addr_add_handler: Lease time: 86400 seconds
[Setup] [INF] ipv4_addr_add_handler: Subnet:
[Setup] [INF] ipv4_addr_add_handler: Router:

The above result depends on your local network. At this point you should be able to connect via telnet over the network. On your linux host:

$ telnet
Telnet escape character is '^]'.
Connected to
Escape character is '^]'.

You are now connected, and as for the UART console, you can type in your commands and get the output through your telnet client.