Paramiko “Unknown Server”

Question

I\'m trying to get started with the Paramiko library, but the library is throwing an exception as soon as I try to connect with the following simple program:

Answer 1

The correct way is either:

• Call the HostKeys.add on the instance returned by SSHClient.get_host_keys before calling the connect, passing it the trusted key.

    from base64 import decodebytes
    # ...
  
    keydata = b"""AAAAB3NzaC1yc2EAAAADAQAB..."""
    key = paramiko.RSAKey(data=decodebytes(keydata))
    client.get_host_keys().add('example.com', 'ssh-rsa', key) 
  

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

  If you know a fingerprint only, see:
  Python - pysftp / paramiko - Verify host key using its fingerprint

• Or load the already cached hostkey (e.g. by the command-line ssh) using client.load_system_host_keys().

• Or you can at least cache the hostkey from the first attempt to make sure it does not change in the future.

  For that use SSHClient.load_host_keys before connect. It makes Paramiko automatically add the new host key to the file (when combined with AutoAddPolicy).