我正在使用 pysftp 下载和上传一些文件。这个完全相同的代码我在一小时前刚刚运行过并且很好，但现在我收到了“协商期间的 EOF”错误。我在这里缺少什么？

>>> sftp = pysftp.Connection(host, username=user, password=pasw)
>>> sftp
<pysftp.Connection object at 0x7f88b25bb410>
>>> sftp.cd('data')
<contextlib.GeneratorContextManager object at 0x7f88b1a86910>
>>> sftp.exists(filename)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/pysftp/__init__.py", line 827, in exists
    self._sftp_connect()
  File "/usr/local/lib/python2.7/dist-packages/pysftp/__init__.py", line 205, in _sftp_connect
    self._sftp = paramiko.SFTPClient.from_transport(self._transport)
  File "/usr/local/lib/python2.7/dist-packages/paramiko/sftp_client.py", line 132, in from_transport
    return cls(chan)
  File "/usr/local/lib/python2.7/dist-packages/paramiko/sftp_client.py", line 101, in __init__
    raise SSHException('EOF during negotiation')
paramiko.ssh_exception.SSHException: EOF during negotiation

EDIT:启用 paramiko.transport 的日志记录并得到以下信息：

>>> import logging; logging.basicConfig(); logging.getLogger('paramiko.transport').setLevel(logging.DEBUG)
>>> sftp = pysftp.Connection(host, username=user, password=pasw)
DEBUG:paramiko.transport:starting thread (client mode): 0x27313b0L
DEBUG:paramiko.transport:Local version/idstring: SSH-2.0-paramiko_1.16.0
DEBUG:paramiko.transport:Remote version/idstring: SSH-2.0-OpenSSH_4.3p2
INFO:paramiko.transport:Connected (version 2.0, client OpenSSH_4.3p2)
DEBUG:paramiko.transport:kex algos:[...] client lang:[u''] server lang:[u''] kex follows?False
DEBUG:paramiko.transport:Kex agreed: diffie-hellman-group1-sha1
DEBUG:paramiko.transport:Cipher agreed: aes128-ctr
DEBUG:paramiko.transport:MAC agreed: hmac-sha2-256
DEBUG:paramiko.transport:Compression agreed: none
DEBUG:paramiko.transport:kex engine KexGroup1 specified hash_algo <built-in function openssl_sha1>
DEBUG:paramiko.transport:Switch to new keys ...
DEBUG:paramiko.transport:Attempting password auth...
DEBUG:paramiko.transport:userauth is OK
INFO:paramiko.transport:Authentication (password) successful!
>>> sftp.cd('data')
<contextlib.GeneratorContextManager object at 0x027371D0>
>>> sftp.exists(filename)
DEBUG:paramiko.transport:[chan 0] Max packet in: 32768 bytes
DEBUG:paramiko.transport:[chan 0] Max packet out: 32768 bytes
DEBUG:paramiko.transport:Secsh channel 0 opened.
DEBUG:paramiko.transport:[chan 0] Sesch channel 0 request ok
Traceback (most recent call last):
DEBUG:paramiko.transport:[chan 0] EOF received (0)
  File "<stdin>", line 1, in <module>
  File "C:\Python27\lib\site-packages\pysftp.py", line 802, in exists
DEBUG:paramiko.transport:[chan 0] EOF sent (0)
    self._sftp_connect()
  File "C:\Python27\lib\site-packages\pysftp.py", line 192, in _sftp_connect
    self._sftp = paramiko.SFTPClient.from_transport(self._transport)
  File "C:\Python27\lib\site-packages\paramiko\sftp_client.py", line 132, in from_transport
    return cls(chan)
  File "C:\Python27\lib\site-packages\paramiko\sftp_client.py", line 101, in __init__
    raise SSHException('EOF during negotiation')
paramiko.ssh_exception.SSHException: EOF during negotiation
>>>

仍然不知道出了什么问题......

我在使用密码身份验证的程序中遇到了同样的错误。发现是因为SFTP服务器上的密码已经过期了。重置它，一切正常。