samples: net: Add FTP client sample

Add a minimal FTP client sample, exposing FTP operations via network
shell.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>

Author: rlubos

samples/net/ftp_client/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(ftp_client)
+
+target_sources(app PRIVATE src/main.c)
+
+include(${ZEPHYR_BASE}/samples/net/common/common.cmake)

samples/net/ftp_client/README.rst

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+.. zephyr:code-sample:: ftp-client
+   :name: FTP client shell sample
+   :relevant-api: ftp_client
+
+   FTP client sample interacting with FTP server over Zephyr shell.
+
+Overview
+********
+
+This sample demonstrates the use of the FTP client library to interact with a
+FTP server running on a host. The FTP commands are exposed via FTP shell module
+provided by Zephyr.
+
+Requirements
+************
+
+- :ref:`networking_with_eth_qemu`, :ref:`networking_with_qemu` or :ref:`networking_with_native_sim`
+- Linux machine
+
+Building and Running
+********************
+
+Build the Zephyr version of the application like this:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/net/ftp_client
+   :board: <board_to_use>
+   :goals: build
+   :compact:
+
+The sample requires a running FTP server to interact with. This for example can
+be achieved by running the Python `pyftpdlib`_ module, which provides built-in
+FTP server functionality:
+
+.. code-block:: bash
+
+   pip install pyftpdlib
+   mkdir file_root
+   echo "some test data" > file_root/test_file.txt
+   python3 -m pyftpdlib -p 2121 --write --directory=file_root
+
+This installs the required Python package, creates a root that the FTP server
+will expose and creates a dummy test file. Note, that the server will run in a
+write-mode, allowing to create, delete and overwrite files and directories - be
+careful when using other root locations than the test directory.
+
+Launch :command:`net-setup.sh` in net-tools:
+
+.. code-block:: bash
+
+   ./net-setup.sh
+
+Build and run the FTP client sample application for native_sim:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/net/ftp_client
+   :host-os: unix
+   :board: native_sim
+   :goals: run
+   :compact:
+
+The sample prints the greeting and exposes the network shell module to interact with:
+
+.. code-block:: console
+
+   [00:00:00.000,000] <inf> net_config: Initializing network
+   [00:00:00.000,000] <inf> net_config: IPv4 address: 192.0.2.1
+   [00:00:00.110,000] <inf> net_config: IPv6 address: 2001:db8::1
+   [00:00:00.110,000] <inf> net_config: IPv6 address: 2001:db8::1
+   [00:00:00.110,000] <inf> ftp_client_sample: Starting FTP client sample
+   [00:00:00.110,000] <inf> ftp_client_sample: Network connectivity established.
+   [00:00:00.110,000] <inf> ftp_client_sample: You can interact with FTP server via shell.
+
+Connect to the FTP server with ``net ftp connect`` command. The server by default
+exposes ``anonymous`` user with dummy password:
+
+.. code-block:: console
+
+   uart:~$ net ftp connect anonymous null 192.0.2.2 2121
+   220 pyftpdlib 2.1.0 ready.
+   530 Log in with USER and PASS first.
+   331 Username ok, send password.
+   230 Login successful.
+
+Once successfully connected, a various FTP commands can be executed to interact
+with the file system on the host.
+
+List directory contents:
+
+.. code-block:: console
+
+   uart:~$ net ftp ls
+   227 Entering passive mode (192,0,2,2,146,7).
+   150 File status okay. About to open data connection.
+   -rw-r--r--   1 user     domain users       15 Feb 20 11:16 test_file.txt
+   226 Transfer complete.
+
+Read file content:
+
+.. code-block:: console
+
+   uart:~$ net ftp get test_file.txt
+   227 Entering passive mode (192,0,2,2,222,177).
+   150 File status okay. About to open data connection.
+   some test data
+   226 Transfer complete.
+
+Create a new directory, change working directory and print the current working directory:
+
+.. code-block:: console
+
+   uart:~$ net ftp mkdir test_dir
+   257 "/test_dir" directory created.
+   uart:~$ net ftp cd test_dir
+   250 "/test_dir" is the current directory.
+   uart:~$ net ftp pwd
+   257 "/test_dir" is the current directory.
+
+Create a new file, print it's content and then remove it:
+
+.. code-block:: console
+
+   uart:~$ net ftp put new_file.txt
+   Input mode (max 2048 characters). End the line with \ to start a new one:
+   New file content\
+
+   227 Entering passive mode (192,0,2,2,131,169).
+   150 File status okay. About to open data connection.
+   226 Transfer complete.
+   uart:~$ net ftp get new_file.txt
+   227 Entering passive mode (192,0,2,2,140,157).
+   150 File status okay. About to open data connection.
+   New file content
+   226 Transfer complete.
+   uart:~$ net ftp rm new_file.txt
+   250 File removed.
+
+Disconnect from the server:
+
+.. code-block:: console
+
+   uart:~$ net ftp disconnect
+   221 Goodbye.
+
+A complete list of supported FTP commands can be listed with ``--help`` parameter:
+
+.. code-block:: console
+
+   uart:~$ net ftp --help
+   ftp - FTP client commands
+   Subcommands:
+     connect     : Connect to FTP server.
+                   Usage: connect <username> <password> <hostname> [<port> <sec_tag>]
+     disconnect  : Disconnect from FTP server.
+                   Usage: disconnect
+     status      : Print connection status.
+                   Usage: status
+     pwd         : Print working directory.
+                   Usage: pwd
+     ls          : List information about folder or file.
+                   Usage: ls [<options> <path>]
+     cd          : Change working directory.
+                   Usage: cd <path>
+     mkdir       : Create directory.
+                   Usage: mkdir <dir_name>
+     rmdir       : Delete directory.
+                   Usage: rmdir <dir_name>
+     rename      : Rename a file.
+                   Usage: rename <old_name> <new_name>
+     rm          : Delete a file.
+                   Usage: rm <file_name>
+     get         : Read file content.
+                   Usage: get <file_name>
+     put         : Write to a file.
+                   Usage: put <file_name> [<data>]
+     append      : Append a file.
+                   Usage: append <file_name> <data>
+     mode        : Select transfer type.
+                   Usage: mode <ascii/binary>
+
+.. _pyftpdlib: https://github.com/giampaolo/pyftpdlib

samples/net/ftp_client/prj.conf

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+CONFIG_ENTROPY_GENERATOR=y
+CONFIG_TEST_RANDOM_GENERATOR=y
+CONFIG_INIT_STACKS=y
+
+CONFIG_NETWORKING=y
+CONFIG_NET_TCP=y
+CONFIG_NET_IPV6=y
+CONFIG_NET_IPV4=y
+CONFIG_NET_LOG=y
+CONFIG_NET_SHELL=y
+
+CONFIG_NET_PKT_RX_COUNT=16
+CONFIG_NET_PKT_TX_COUNT=16
+CONFIG_NET_BUF_RX_COUNT=64
+CONFIG_NET_BUF_TX_COUNT=64
+
+CONFIG_NET_CONFIG_SETTINGS=y
+CONFIG_NET_CONFIG_NEED_IPV6=y
+CONFIG_NET_CONFIG_NEED_IPV4=y
+CONFIG_NET_CONFIG_MY_IPV6_ADDR="2001:db8::1"
+CONFIG_NET_CONFIG_PEER_IPV6_ADDR="2001:db8::2"
+CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.0.2.1"
+CONFIG_NET_CONFIG_PEER_IPV4_ADDR="192.0.2.2"
+
+CONFIG_FTP_CLIENT=y
+CONFIG_DNS_RESOLVER=y

samples/net/ftp_client/sample.yaml

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+common:
+  harness: net
+  depends_on: netif
+  tags:
+    - net
+sample:
+  name: FTP client
+tests:
+  sample.net.ftp_client: {}

samples/net/ftp_client/src/main.c

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+/*
+ * Copyright (c) 2026 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(ftp_client_sample, LOG_LEVEL_DBG);
+
+#include <zephyr/kernel.h>
+
+#include "net_sample_common.h"
+
+int main(void)
+{
+	LOG_INF("Starting FTP client sample");
+
+	wait_for_network();
+
+	LOG_INF("Network connectivity established.");
+	LOG_INF("You can interact with FTP server via shell.");
+
+	k_sleep(K_FOREVER);
+
+	return 0;
+}