SSH tunnel in Python

py-tunnel1.py

# Create an SSH tunnel in Python.
# In this example we suppose we are in a firewalled network where we cannot
# access GMAIL IMAP server on port 993.
# So we create a tunnel to a machine out of the firewalled network and forward
# to GMAIL IMAP server.
#
# Requirements:
# pip install paramiko
#
# Inspired by:
# https://github.com/paramiko/paramiko/blob/master/demos/forward.py
#
# UPDATE: check the other Gist in this folder!

import paramiko
import select
import time
import thread

try:
    import SocketServer
except ImportError:
    import socketserver as SocketServer


class Handler(SocketServer.BaseRequestHandler):
    def handle(self):
        try:
            chan = self.ssh_transport.open_channel('direct-tcpip',
                                                   (self.chain_host,
                                                    self.chain_port),
                                                   self.request.getpeername())
        except Exception as e:
            print('Incoming request to %s:%d failed: %s' % (self.chain_host,
                                                            self.chain_port,
                                                            repr(e)))
            return
        if chan is None:
            print('Incoming request to %s:%d was rejected by the SSH server.' %
                  (self.chain_host, self.chain_port))
            return

        print(
            'Connected!  Tunnel open %r -> %r -> %r' % (
            self.request.getpeername(),
            chan.getpeername(), (
                self.chain_host,
                self.chain_port)))
        while True:
            r, w, x = select.select([self.request, chan], [], [])
            if self.request in r:
                data = self.request.recv(1024)
                if len(data) == 0:
                    break
                chan.send(data)
            if chan in r:
                data = chan.recv(1024)
                if len(data) == 0:
                    break
                self.request.send(data)

        peername = self.request.getpeername()
        chan.close()
        self.request.close()
        print('Tunnel closed from %r' % (peername,))


class Tunnel:
    def __init__(self,
                 remote_address,
                 remote_port,
                 remote_username,
                 remote_password,
                 remote_forward_address,
                 remote_forward_port,
                 local_bind_address,
                 local_bind_port):
        self.remote_address = remote_address
        self.remote_port = remote_port
        self.remote_username = remote_username
        self.remote_password = remote_password
        self.remote_forward_address = remote_forward_address
        self.remote_forward_port = remote_forward_port
        self.local_bind_address = local_bind_address
        self.local_bind_port = local_bind_port

    def start(self):
        self.client = paramiko.SSHClient()
        self.client.load_system_host_keys()
        self.client.set_missing_host_key_policy(paramiko.WarningPolicy())
        self.client.connect(
                self.remote_address,
                self.remote_port,
                username=self.remote_username,
                password=self.remote_password,
                key_filename=None,
                look_for_keys=False)

        h = Handler
        h.chain_host = self.remote_forward_address
        h.chain_port = self.remote_forward_port
        h.ssh_transport = self.client.get_transport()
        self.forwarder = SocketServer.ThreadingTCPServer(
                (self.local_bind_address, self.local_bind_port), h)
        self.forwarder.daemon_threads = True
        self.forwarder.allow_reuse_address = True

        thread.start_new_thread(self.forwarder.serve_forever, ())
        time.sleep(.5)

    def stop(self):
        self.client.close()
        self.forwarder.shutdown()
        self.forwarder.server_close()


def main():
    print 'START'

    params = dict(
            remote_address='00.84.23.000',
            remote_port=443,
            remote_username='myself',
            remote_password='mypassword',
            remote_forward_address='imap.gmail.com',
            remote_forward_port=993,
            local_bind_address='localhost',
            local_bind_port=6666
    )
    tunnel = Tunnel(**params)
    tunnel.start()

    print 'STARTING IMAP comunication...'
    import imaplib
    mail = imaplib.IMAP4_SSL(params['local_bind_address'],
                             port=params['local_bind_port'])
    mail.login('[email protected]', 'mygmailpassword')
    print mail.list()

    tunnel.stop()

    print 'Now you can check that there is nothing listening on port {}.'.format(
            params['local_bind_port'])
    print 'Just run:'
    print '$ netstat -an | grep {}'.format(params['local_bind_port'])
    _ = raw_input('Press any key to quit: ')


if __name__ == '__main__':
    main()

py-tunnel2.py

# Create an SSH tunnel in Python.
# In this example we suppose we are in a firewalled network where we cannot
# access GMAIL IMAP server on port 993.
# So we create a tunnel to a machine out of the firewalled network and forward
# to GMAIL IMAP server.
#
# Requirements:
# pip install sshtunnel

from sshtunnel import open_tunnel
import imaplib


params = dict (
    ssh_address='00.84.23.000',
    ssh_port=443,
    ssh_host_key=None,
    ssh_username='myusername',
    ssh_password='mypassword',
    ssh_private_key=None,
    remote_bind_address=('imap.gmail.com', 993),
    local_bind_address=('localhost', 6666),
)
with open_tunnel(**params):
    mail = imaplib.IMAP4_SSL(*params['local_bind_address'])
    mail.login('[email protected]', 'mygmailpassword')
    print mail.list()

print 'Now you can check that there is nothing listening on port {}.'.format(
        params['local_bind_address'][1])
print 'Just run:'
print '$ netstat -an | grep {}'.format(params['local_bind_address'][1])
_ = raw_input('Press any key to quit: ')