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Author: Pahaz_

Repo: https://github.com/pahaz/sshtunnel/

Inspired by https://github.com/jmagnusson/bgtunnel, which doesn't work on Windows.

See also: https://github.com/paramiko/paramiko/blob/master/demos/forward.py

Requirements

• paramiko_

Installation

sshtunnel_ is on PyPI, so simply run:

::

pip install sshtunnel

or ::

easy_install sshtunnel

or ::

conda install -c conda-forge sshtunnel

to have it installed in your environment.

For installing from source, clone the repo <https://github.com/pahaz/sshtunnel>_ and run::

python setup.py install

Testing the package

In order to run the tests you first need tox <https://testrun.org/tox/latest/>_ and run::

python setup.py test

Usage scenarios

One of the typical scenarios where sshtunnel is helpful is depicted in the figure below. User may need to connect a port of a remote server (i.e. 8080) where only SSH port (usually port 22) is reachable. ::

----------------------------------------------------------------------

                            |
-------------+              |    +----------+
    LOCAL    |              |    |  REMOTE  | :22 SSH
    CLIENT   | <== SSH ========> |  SERVER  | :8080 web service
-------------+              |    +----------+
                            |
                         FIREWALL (only port 22 is open)

----------------------------------------------------------------------

Fig1: How to connect to a service blocked by a firewall through SSH tunnel.

If allowed by the SSH server, it is also possible to reach a private server (from the perspective of REMOTE SERVER) not directly visible from the outside (LOCAL CLIENT's perspective). ::

----------------------------------------------------------------------

                            |
-------------+              |    +----------+               +---------
    LOCAL    |              |    |  REMOTE  |               | PRIVATE
    CLIENT   | <== SSH ========> |  SERVER  | <== local ==> | SERVER
-------------+              |    +----------+               +---------
                            |
                         FIREWALL (only port 443 is open)

----------------------------------------------------------------------

Fig2: How to connect to PRIVATE SERVER through SSH tunnel.

Usage examples

API allows either initializing the tunnel and starting it or using a with context, which will take care of starting and stopping the tunnel:

Example 1

Code corresponding to Fig1 above follows, given remote server's address is pahaz.urfuclub.ru, password authentication and randomly assigned local bind port.

.. code-block:: python

from sshtunnel import SSHTunnelForwarder

server = SSHTunnelForwarder(
    'alfa.8iq.dev',
    ssh_username="pahaz",
    ssh_password="secret",
    remote_bind_address=('127.0.0.1', 8080)
)

server.start()

print(server.local_bind_port)  # show assigned local port
# work with `SECRET SERVICE` through `server.local_bind_port`.

server.stop()

Example 2

Example of a port forwarding to a private server not directly reachable, assuming password protected pkey authentication, remote server's SSH service is listening on port 443 and that port is open in the firewall (Fig2):

.. code-block:: python

import paramiko
import sshtunnel

with sshtunnel.open_tunnel(
    (REMOTE_SERVER_IP, 443),
    ssh_username="",
    ssh_pkey="/var/ssh/rsa_key",
    ssh_private_key_password="secret",
    remote_bind_address=(PRIVATE_SERVER_IP, 22),
    local_bind_address=('0.0.0.0', 10022)
) as tunnel:
    client = paramiko.SSHClient()
    client.load_system_host_keys()
    client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    client.connect('127.0.0.1', 10022)
    # do some operations with client session
    client.close()

print('FINISH!')

Example 3

Example of a port forwarding for the Vagrant MySQL local port:

.. code-block:: python

from sshtunnel import open_tunnel
from time import sleep

with open_tunnel(
    ('localhost', 2222),
    ssh_username="vagrant",
    ssh_password="vagrant",
    remote_bind_address=('127.0.0.1', 3306)
) as server:

    print(server.local_bind_port)
    while True:
        # press Ctrl-C for stopping
        sleep(1)

print('FINISH!')

Or simply using the CLI:

.. code-block:: console

(bash)$ python -m sshtunnel -U vagrant -P vagrant -L :3306 -R 127.0.0.1:3306 -p 2222 localhost

Example 4

Opening an SSH session jumping over two tunnels. SSH transport and tunnels will be daemonised, which will not wait for the connections to stop at close time.

.. code-block:: python

import sshtunnel
from paramiko import SSHClient


with sshtunnel.open_tunnel(
    ssh_address_or_host=('GW1_ip', 20022),
    remote_bind_address=('GW2_ip', 22),
) as tunnel1:
    print('Connection to tunnel1 (GW1_ip:GW1_port) OK...')
    with sshtunnel.open_tunnel(
        ssh_address_or_host=('localhost', tunnel1.local_bind_port),
        remote_bind_address=('target_ip', 22),
        ssh_username='GW2_user',
        ssh_password='GW2_pwd',
    ) as tunnel2:
        print('Connection to tunnel2 (GW2_ip:GW2_port) OK...')
        with SSHClient() as ssh:
            ssh.connect('localhost',
                port=tunnel2.local_bind_port,
                username='target_user',
                password='target_pwd',
            )
            ssh.exec_command(...)

CLI usage

::

$ sshtunnel --help
usage: sshtunnel [-h] [-U SSH_USERNAME] [-p SSH_PORT] [-P SSH_PASSWORD] -R
                 IP:PORT [IP:PORT ...] [-L [IP:PORT ...]] [-k SSH_HOST_KEY]
                 [-K KEY_FILE] [-S KEY_PASSWORD] [-t] [-v] [-V] [-x IP:PORT]
                 [-c SSH_CONFIG_FILE] [-z] [-n] [-d [FOLDER ...]]
                 ssh_address

Pure python ssh tunnel utils
Version 0.4.0

positional arguments:
  ssh_address           SSH server IP address (GW for SSH tunnels)
                        set with "-- ssh_address" if immediately after -R or -L