SSHTUNNEL(1) sshtunnel SSHTUNNEL(1)

sshtunnel - sshtunnel Documentation

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license

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

•
paramiko

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 and run:

python setup.py install

In order to run the tests you first need tox and run:

python setup.py test

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.

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

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

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 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):

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 of a port forwarding for the Vagrant MySQL local port:

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:

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

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.

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(...)
$ sshtunnel --help
usage: sshtunnel [-h] [-U SSH_USERNAME] [-p SSH_PORT] [-P SSH_PASSWORD] -R
                 IP:PORT [IP:PORT ...] [-L [IP:PORT [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 [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
optional arguments:
  -h, --help            show this help message and exit
  -U SSH_USERNAME, --username SSH_USERNAME
                        SSH server account username
  -p SSH_PORT, --server_port SSH_PORT
                        SSH server TCP port (default: 22)
  -P SSH_PASSWORD, --password SSH_PASSWORD
                        SSH server account password
  -R IP:PORT [IP:PORT ...], --remote_bind_address IP:PORT [IP:PORT ...]
                        Remote bind address sequence: ip_1:port_1 ip_2:port_2 ... ip_n:port_n
                        Equivalent to ssh -Lxxxx:IP_ADDRESS:PORT
                        If port is omitted, defaults to 22.
                        Example: -R 10.10.10.10: 10.10.10.10:5900
  -L [IP:PORT [IP:PORT ...]], --local_bind_address [IP:PORT [IP:PORT ...]]
                        Local bind address sequence: ip_1:port_1 ip_2:port_2 ... ip_n:port_n
                        Elements may also be valid UNIX socket domains:
                        /tmp/foo.sock /tmp/bar.sock ... /tmp/baz.sock
                        Equivalent to ssh -LPORT:xxxxxxxxx:xxxx, being the local IP address optional.
                        By default it will listen in all interfaces (0.0.0.0) and choose a random port.
                        Example: -L :40000
  -k SSH_HOST_KEY, --ssh_host_key SSH_HOST_KEY
                        Gateway's host key
  -K KEY_FILE, --private_key_file KEY_FILE
                        RSA/DSS/ECDSA private key file
  -S KEY_PASSWORD, --private_key_password KEY_PASSWORD
                        RSA/DSS/ECDSA private key password
  -t, --threaded        Allow concurrent connections to each tunnel
  -v, --verbose         Increase output verbosity (default: ERROR)
  -V, --version         Show version number and quit
  -x IP:PORT, --proxy IP:PORT
                        IP and port of SSH proxy to destination
  -c SSH_CONFIG_FILE, --config SSH_CONFIG_FILE
                        SSH configuration file, defaults to ~/.ssh/config
  -z, --compress        Request server for compression over SSH transport
  -n, --noagent         Disable looking for keys from an SSH agent
  -d [FOLDER [FOLDER ...]], --host_pkey_directories [FOLDER [FOLDER ...]]
                        List of directories where SSH pkeys (in the format `id_*`) may be found

sshtunnel - Initiate SSH tunnels via a remote gateway.

sshtunnel works by opening a port forwarding SSH connection in the background, using threads.

The connection(s) are closed when explicitly calling the SSHTunnelForwarder.stop() method or using it as a context.

Timeout (seconds) for transport socket (socket.settimeout)
Timeout (seconds) for tunnel connection (open_channel timeout)
default level if no logger passed (ERROR)
Path of optional ssh configuration file
Check if the format of the address is correct
(str, int) representing an IP address and port, respectively

NOTE:

alternatively a local address can be a str when working with UNIX domain sockets, if supported by the platform
raised when address has an incorrect format
>>> check_address(('127.0.0.1', 22))
Check if the format of the addresses is correct
Sequence of (str, int) pairs, each representing an IP address and port respectively

NOTE:

when supported by the platform, one or more of the elements in the list can be of type str, representing a valid UNIX domain socket
Whether or not the address list
raised when address_list contains an invalid element
raised when any address in the list has an incorrect format

Example:

>>> check_addresses([('127.0.0.1', 22), ('127.0.0.1', 2222)])
Attach or create a new logger and add a console handler if not present

Arguments:

logging.Logger instance; a new one is created if this argument is empty
logging.Logger's level, either as a string (i.e. ERROR) or in numeric format (10 == DEBUG)

NOTE:

a value of 1 == TRACE enables Tracing mode
Enable/disable capturing the events logged by the warnings module into logger's handlers

Default: True

NOTE:

ignored in python 2.6
Whether or not add a console handler for paramiko.transport's logger if no handler present

Default: True

logging.Logger
Exception raised by SSHTunnelForwarder errors
Exception for Tunnel forwarder errors
SSH tunnel class
  • Initialize a SSH tunnel to a remote host according to the input arguments
  • Read an SSH configuration file (typically ~/.ssh/config)
  • Load keys from a running SSH agent (i.e. Pageant, GNOME Keyring)

Raises:

raised by SSHTunnelForwarder class methods
raised by tunnel forwarder threads

NOTE:

Attributes mute_exceptions and raise_exception_if_any_forwarder_have_a_problem (deprecated) may be used to silence most exceptions raised from this class

Keyword Arguments:

IP or hostname of REMOTE GATEWAY. It may be a two-element tuple (str, int) representing IP and port respectively, or a str representing the IP address only

New in version 0.0.4.

SSH configuration file that will be read. If explicitly set to None, parsing of this configuration is omitted

Default: SSH_CONFIG_FILE

New in version 0.0.4.

Representation of a line in an OpenSSH-style "known hosts" file.

REMOTE GATEWAY's key fingerprint will be compared to this host key in order to prevent against SSH server spoofing. Important when using passwords in order not to accidentally do a login attempt to a wrong (perhaps an attacker's) machine

Username to authenticate as in REMOTE SERVER

Default: current local user name

Text representing the password used to connect to REMOTE SERVER or for unlocking a private key.

NOTE:

Avoid coding secret password directly in the code, since this may be visible and make your service vulnerable to attacks
Optional port number of the SSH service on REMOTE GATEWAY, when ssh_address_or_host` is a str representing the IP part of REMOTE GATEWAY's address

Default: 22

Private key file name (str) to obtain the public key from or a public key (paramiko.pkey.PKey)
Password for an encrypted ssh_pkey

NOTE:

Avoid coding secret password directly in the code, since this may be visible and make your service vulnerable to attacks
Proxy where all SSH traffic will be passed through. It might be for example a paramiko.proxy.ProxyCommand instance. See either the paramiko.transport.Transport's sock parameter documentation or ProxyCommand in ssh_config(5) for more information.

It is also possible to specify the proxy address as a tuple of type (str, int) representing proxy's IP and port

NOTE:

Ignored if ssh_proxy_enabled is False

New in version 0.0.5.

Enable/disable SSH proxy. If True and user's ssh_config_file contains a ProxyCommand directive that matches the specified ssh_address_or_host, a paramiko.proxy.ProxyCommand object will be created where all SSH traffic will be passed through

Default: True

New in version 0.0.4.

Local tuple in the format (str, int) representing the IP and port of the local side of the tunnel. Both elements in the tuple are optional so both ('', 8000) and ('10.0.0.1', ) are valid values

Default: ('0.0.0.0', RANDOM_PORT)

Changed in version 0.0.8: Added the ability to use a UNIX domain socket as local bind address

In case more than one tunnel is established at once, a list of tuples (in the same format as local_bind_address) can be specified, such as [(ip1, port_1), (ip_2, port2), ...]

Default: [local_bind_address]

New in version 0.0.4.

Remote tuple in the format (str, int) representing the IP and port of the remote side of the tunnel.
In case more than one tunnel is established at once, a list of tuples (in the same format as remote_bind_address) can be specified, such as [(ip1, port_1), (ip_2, port2), ...]

Default: [remote_bind_address]

New in version 0.0.4.

Enable/disable load of keys from an SSH agent

Default: True

New in version 0.0.8.

Look for pkeys in folders on this list, for example ['~/.ssh'].

Default: None (disabled)

New in version 0.1.4.

Turn on/off transport compression. By default compression is disabled since it may negatively affect interactive sessions

Default: False

New in version 0.0.8.

logging instance for sshtunnel and paramiko

Default: logging.Logger instance with a single logging.StreamHandler handler and DEFAULT_LOGLEVEL level

New in version 0.0.3.

Allow silencing BaseSSHTunnelForwarderError or HandlerSSHTunnelForwarderError exceptions when enabled

Default: False

New in version 0.0.8.

Interval in seconds defining the period in which, if no data was sent over the connection, a 'keepalive' packet will be sent (and ignored by the remote host). This can be useful to keep connections alive over a NAT. You can set to 0.0 for disable keepalive.

Default: 5.0 (no keepalive packets are sent)

New in version 0.0.7.

Allow concurrent connections over a single tunnel

Default: True

New in version 0.0.3.

Superseded by ssh_address_or_host, tuple of type (str, int) representing the IP and port of REMOTE SERVER

Deprecated since version 0.0.4.

Superseded by ssh_address_or_host, tuple of type (str, int) representing the IP and port of REMOTE SERVER

Deprecated since version 0.0.4.

Superseded by ssh_pkey, which can represent either a private key file name (str) or a public key (paramiko.pkey.PKey)

Deprecated since version 0.0.8.

Allow silencing BaseSSHTunnelForwarderError or HandlerSSHTunnelForwarderError exceptions when set to False

Default: True

New in version 0.0.4.

Deprecated since version 0.0.8: (use mute_exceptions instead)

Attributes:

Describe whether or not the other side of the tunnel was reported to be up (and we must close it) or not (skip shutting down that tunnel)

NOTE:

This attribute should not be modified

NOTE:

When skip_tunnel_checkup is disabled or the local bind is a UNIX socket, the value will always be True

Example:

{('127.0.0.1', 55550): True,   # this tunnel is up
 ('127.0.0.1', 55551): False}  # this one isn't

where 55550 and 55551 are the local bind ports

Disable tunnel checkup (default for backwards compatibility).

New in version 0.1.0.

flag tunnel threads in daemon mode
flag SSH transport thread in daemon mode
Check if a tunnel is up (remote target's host is reachable on TCP target's port)
tuple of type (str, int) indicating the listen IP address and port
boolean

Deprecated since version 0.1.0: Replaced by check_tunnels() and tunnel_is_up

Check that if all tunnels are established and populates tunnel_is_up
Load public keys from any available SSH agent
logger (Optional[logging.Logger])
list
Load public keys from any available SSH agent or local .ssh directory.
logger (Optional[logging.Logger])
List of local directories where host SSH pkeys in the format "id_*" are searched. For example, ['~/.ssh']

New in version 0.1.0.

Whether or not load keys from agent

Default: False

list
Get SSH Public key from a private key file, given an optional password
File containing a private key (RSA, DSS or ECDSA)
Password to decrypt the private key

logger (Optional[logging.Logger])

paramiko.Pkey
Start the SSH tunnels
Shut the tunnel down. By default we are always waiting until closing all connections. You can use force=True to force close connections
Force close current connections

Default: False

New in version 0.2.2.

NOTE:

This had to be handled with care before 0.1.0:
  • if a port redirection is opened
  • the destination is not reachable
  • we attempt a connection to that tunnel (SYN is sent and acknowledged, then a FIN packet is sent and never acknowledged... weird)
  • we try to shutdown: it will not succeed until FIN_WAIT_2 and CLOSE_WAIT time out.

NOTE:

Handle these scenarios with tunnel_is_up: if False, server shutdown() will be skipped on that tunnel
Stop the an active tunnel, alias to stop()
Restart connection to the gateway and tunnels
Return a list containing the ports of local side of the TCP tunnels
Return a list containing the IP addresses listening for the tunnels
Return a list of (IP, port) pairs for the local side of the tunnels
Return a dictionary containing the active local<>remote tunnel_bindings
Return True if the underlying SSH transport is up
Open an SSH Tunnel, wrapper for SSHTunnelForwarder
SSH server's IP address and port in the format (ssh_address, ssh_port)
log level for logging.Logger instance, i.e. DEBUG
Enable/disable the local side check and populate tunnel_is_up

Default: True

New in version 0.1.0.

NOTE:

A value of debug_level set to 1 == TRACE enables tracing mode

NOTE:

See SSHTunnelForwarder for keyword arguments

Example:

from sshtunnel import open_tunnel
with open_tunnel(SERVER,
                 ssh_username=SSH_USER,
                 ssh_port=22,
                 ssh_password=SSH_PASSWORD,
                 remote_bind_address=(REMOTE_HOST, REMOTE_PORT),
                 local_bind_address=('', LOCAL_PORT)) as server:
    def do_something(port):
        pass
    print("LOCAL PORTS:", server.local_bind_port)
    do_something(server.local_bind_port)
  • Cameron Maske
  • Gustavo Machado
  • Colin Jermain
  • JM Fernández - (big thanks!)
  • Lewis Thompson
  • Erik Rogers
  • Mart Sõmermaa
  • Chronial
  • Dan Harbin
  • Ignacio Peluffo
  • Niels Zeilemaker
  • Georgy Rylov
  • Eddie Chiang
  • kkrasovskii
•
  • Change the daemon mod flag for all tunnel threads (is not fully backward compatible) to prevent unexpected hangs (#219)
  • Add docker based end to end functinal tests for Mongo/Postgres/MySQL (#219)
  • Add docker based end to end hangs tests (#219)
•
  • Fix host key directory detection
  • Unify default ssh config folder to ~/.ssh
•
•
Increase open connection timeout to 10 secods
•
  • Change default with context behavior to use .stop(force=True) on exit (is not fully backward compatible)
  • Remove useless daemon_forward_servers = True hack for hangs prevention (is not fully backward compatible)
  • Set transport keepalive to 5 second by default (disabled for version < 0.3.0)
  • Set default transport timeout to 0.1
  • Deprecate and remove block_on_close option
  • Fix "deadlocks" / "tunneling hangs" (#173, #201, #162, #211)
•
•
Add .stop(force=True) for force close active connections (#201)
•
•
Fixes bug with orphan thread for a tunnel that is DOWN (#170)
•
•
Support IPv6 without proxy command. Use built-in paramiko create socket logic. The logic tries to use ipv6 socket family first, then ipv4 socket family.
•
•
Introduce block_on_close attribute
•
•
Allow loading pkeys from ~/.ssh
•
  • pkey_file parameter updated to accept relative paths to user folder using ~
  • Several bugfixes
•
•
Fix #77
•
•
Fix #72
•
  • Add tunnel_bindings property
  • Several bugfixes (#49, #56, #57, #59, #60, #62, #64, #66, ...) (Pahaz, JM Fernández)
  • Add TRACE logging level (JM Fernández)
  • Code and tests refactoring (JM Fernández)
  • Drop python3.2 support
•
  • Merge #31: Support Unix domain socket (local) forwarding (Dan Harbin)
  • Simplify API (JM Fernández)
  • Add sphinx-based documentation (JM Fernández)
  • Add allow_agent (fixes #36, #46) (JM Fernández)
  • Add compression (JM Fernández)
  • Add __str__ method (JM Fernández)
  • Add test functions (JM Fernández)
  • Fix default username when not provided and ssh_config file is skipped (JM Fernández)
  • Fix gateway IP unresolvable exception catching (JM Fernández)
  • Minor fixes (JM Fernández)
  • Add AppVeyor support (JM Fernández)
•
  • Tunnels can now be stopped and started safely (#41) (JM Fernández)
  • Add timeout to SSH gateway and keep-alive messages (#29) (JM Fernández)
  • Allow sending a pkey directly (#43) (Chronial)
  • Add -V CLI option to show current version (JM Fernández)
  • Add coverage (JM Fernández)
  • Refactoring (JM Fernández)
•
•
add -S CLI options for ssh private key password support (Pahaz)
•
  • add ssh_proxy argument, as well as ssh_config(5) ProxyCommand support (Lewis Thompson)
  • add some python 2.6 compatibility fixes (Mart Sõmermaa)
  • paramiko.transport inherits handlers of loggers passed to SSHTunnelForwarder (JM Fernández)
  • fix #34, #33, code style and docs (JM Fernández)
  • add tests (Pahaz)
  • add CI integration (Pahaz)
  • normal packaging (Pahaz)
  • disable check distenation socket connection by SSHTunnelForwarder.local_is_up (Pahaz) [changed default behavior]
  • use daemon mode = False in all threads by default; detail (Pahaz) [changed default behavior]
•
•
fix issue #24 - hide ssh password in logs (Pahaz)
•
•
fix default port issue #19 (Pahaz)
•
•
fix Thread.daemon mode for Python < 3.3 #16, #21 (Lewis Thompson, Erik Rogers)
•
•
fix CLI issues #13 (Pahaz)
•
  • daemon mode by default for all threads (JM Fernández, Pahaz) - incompatible
  • move make_ssh_forward_server to SSHTunnelForwarder.make_ssh_forward_server (Pahaz, JM Fernández) - incompatible
  • move make_ssh_forward_handler to SSHTunnelForwarder.make_ssh_forward_handler_class (Pahaz, JM Fernández) - incompatible
  • rename open to open_tunnel (JM Fernández) - incompatible
  • add CLI interface (JM Fernández)
  • support opening several tunnels at once (JM Fernández)
  • improve stability and readability (JM Fernández, Pahaz)
  • improve logging (JM Fernández, Pahaz)
  • add raise_exception_if_any_forwarder_have_a_problem argument for opening several tunnels at once (Pahaz)
  • add ssh_config_file argument support (JM Fernández)
  • add Python 3 support (JM Fernández, Pahaz)
•
  • add threaded option (Cameron Maske)
  • fix exception error message, correctly printing destination address (Gustavo Machado)
  • fix pip install failure (Colin Jermain, Pahaz)
•
  • SSHTunnelForwarder class (Pahaz)
  • open function (Pahaz)

Copyright (c) 2014-2019 Pahaz White

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Pahaz White

2014-2024, Pahaz White and contributors

April 8, 2024 0.4.0