Paramiko "Unknown Server"

Paramiko Unknown Server

The exception was raised because you are missing a host key, the rather cryptic "Unknown server" is the clue - since the exception was raised from missing_host_key

Try this instead:

import paramiko

paramiko.util.log_to_file('ssh.log') # sets up logging

client = paramiko.SSHClient()
client.load_system_host_keys()
client.connect('127.0.0.1', username=username, password=password)
stdin, stdout, stderr = client.exec_command('ls -l')

Paramiko “Unknown Server”

If this is a private host key file in your home directory, you should not use load_system_host_keys but load_host_keys.

Just out of curiosity, where did you get your host key for that particular host if you did not use set_missing_host_key_policy? If you copied it from your .ssh directory, it is possible that the key file format is different. There are several.

You can test it by adding AutoAdd missing host key policy once and pointing to an empty private host key file. Your login should succeed now (assuming authentication succeeds). Whether it succeeds or fails, your private host key file should now contain the host key in the correct format. You can verify it works by removing the missing host key policy setting and running the script again. It should not moan about missing host keys anymore.

This works for me:

from paramiko import SSHClient
import paramiko

client = SSHClient()
client.load_host_keys(filename='/home/test/stest/kknown_hosts')
# client.set_missing_host_key_policy(paramiko.AutoAddPolicy())

client.connect(hostname='137.xx.x.x')
stdin, stdout, stderr = client.exec_command('ls -l')

Hope this helps,
Hannu

Paramiko SSH failing with Server '...' not found in known_hosts when run on web server

You can hard-code the host key in your Python code, using HostKeys.add:

import paramiko
from base64 import decodebytes

keydata = b"""AAAAB3NzaC1yc2EAAAABIwAAAQEA0hV..."""
key = paramiko.RSAKey(data=decodebytes(keydata))
 
client = paramiko.SSHClient()
client.get_host_keys().add('example.com', 'ssh-rsa', key)
client.connect(...)

• This is based on my answer to:
  
  Paramiko "Unknown Server".

• To see how to obtain the fingerprint for use in the code, see my answer to:
  
  Verify host key with pysftp.

• If using pysftp, instead of Paramiko directly, see:
  
  PySFTP failing with "No hostkey for host X found" when deploying Django/Heroku

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Or, as you are connecting within a private network, you can give up on verifying host key altogether, using AutoAddPolicy:

client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect(...)

(This can be done only if you really do not need the connection to be secure)

Unable to connect to remote host using paramiko?

Maybe you are missing the missing_host_key_policy

What about this one:

proxy = None
client = paramiko.SSHClient()
client.load_system_host_keys()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect(host['hostname'], username=host['user'], sock=proxy)

more examples here: www.programcreek.com

SSHParamiko is giving unknown error when calling the main connection in two different functions

Check that you are calling connect method before calling sftp_connect.

Always call connect first

try this

import ssh_module

class server():

    def host(self):
       ip='127.0.0.1'
       passwd='xyz'
       connection = ssh_module.ssh_connection('abc',passwd,22,ip)
       print "Connec:"
       connection.connect()
       print 'Connected'
       connection.close()
       self.set_directory(ip,passwd)

    def set_directory(self,ip,passwd):
      connection1 = ssh_module.ssh_connection('abc',passwd,22,ip)
      connection1.connect() # Connect before use.
      connection1.execute('x.txt')
      connection1.close()
main=server()
main.host()

Paramiko close connection doesn't work

This is the correct way to go about it

import paramiko

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect()

ftp = ssh.open_sftp()

ftp.close()
ssh.close()

You need to close the ssh instance as well as the sftp.

paramiko.transport throws runtime ValueError while connecting to remote server using ssh

I had the same issue, using PyInstaller - 2.1, other versions same as you.

Downgrading paramiko to version 1.17 and rebuilding the exe with PyInstaller solved the issue for me,

pip uninstall paramiko
pip install paramiko==1.17

Paramiko: Add host_key to known_hosts permanently

From the package documentation, compare

client.load_system_host_keys(filename=None)

Load host keys from a system (read-only) file.  Host keys read with
this method will not be saved back by `save_host_keys`.

with

client.load_host_keys(filename)

Load host keys from a local host-key file.  Host keys read with this
method will be checked after keys loaded via `load_system_host_keys`,
but will be saved back by `save_host_keys` (so they can be modified).
The missing host key policy `.AutoAddPolicy` adds keys to this set and
saves them, when connecting to a previously-unknown server.

So to make Paramiko store any new host keys, you need to use load_host_keys, not load_system_host_keys. E.g.

client.load_host_keys(os.path.expanduser('~/.ssh/known_hosts'))

But it's generally a good idea to avoid using AutoAddPolicy, since it makes you open to man-in-the-middle attacks. What I ended up doing was to generate a local known_hosts in the same folder as the script:

ssh -o GlobalKnownHostsFile=/dev/null -o UserKnownHostsFile=./known_hosts user@host

and then load this file instead:

client.load_host_keys(os.path.join(os.path.dirname(__file__), 'known_hosts'))

This way I can distribute the known_hosts together with my script and run it on different machines without touching the actual known_hosts on those machines.

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