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Netmiko code to enter Juniper CLI is not robust enough

See original GitHub issue

Hello,

I am trying to make Netmiko work with my Juniper EX4200-24P device, but I am always getting:

  File "/tmp/test/venv/lib/python3.9/site-packages/paramiko/channel.py", line 699, in recv
    out = self.in_buffer.read(nbytes, self.timeout)
  File "/tmp/test/venv/lib/python3.9/site-packages/paramiko/buffered_pipe.py", line 164, in read
    raise PipeTimeout()
paramiko.buffered_pipe.PipeTimeout

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/base_connection.py", line 573, in _read_channel_expect
    new_data = self.remote_conn.recv(MAX_BUFFER)
  File "/tmp/test/venv/lib/python3.9/site-packages/paramiko/channel.py", line 701, in recv
    raise socket.timeout()
socket.timeout

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/tmp/test/pokus.py", line 23, in <module>
    ssh = ConnectHandler(**juniper)
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/ssh_dispatcher.py", line 326, in ConnectHandler
    return ConnectionClass(*args, **kwargs)
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/juniper/juniper.py", line 20, in __init__
    return super().__init__(*args, **kwargs)
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/base_connection.py", line 350, in __init__
    self._open()
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/base_connection.py", line 356, in _open
    self._try_session_preparation()
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/base_connection.py", line 792, in _try_session_preparation
    self.session_preparation()
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/juniper/juniper.py", line 26, in session_preparation
    self.set_terminal_width(command=cmd, pattern=r"Screen width set to")
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/base_connection.py", line 1131, in set_terminal_width
    output = self.read_until_pattern(pattern=pattern)
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/base_connection.py", line 655, in read_until_pattern
    return self._read_channel_expect(*args, **kwargs)
  File "/tmp/test/venv/lib/python3.9/site-packages/netmiko/base_connection.py", line 583, in _read_channel_expect
    raise NetmikoTimeoutException(
netmiko.ssh_exception.NetmikoTimeoutException: Timed-out reading channel, data not available.

I’ve tried putting several values for delay_factor, turning off global_cmd_verify, setting max_loops to different values, nothing helped. I did try to turn on the Netmiko debugging, looks to me it never enters the CLI mode, but I don’t understand why. I am perfectly able to run the very same command when I connect with the same user manually via SSH.

The code I am trying with:

from netmiko import ConnectHandler

import logging
logging.basicConfig(filename='test.log', level=logging.DEBUG)
logger = logging.getLogger("netmiko")

juniper = {
    'device_type': 'juniper',
    'host': '192.168.100.9',
    'username': 'root',
    'password': '<password here>',
    'global_cmd_verify': False
}

ssh = ConnectHandler(**juniper)
result = ssh.send_command('show system uptime', delay_factor=5)
print(result)

Debug log:

DEBUG:paramiko.transport:starting thread (client mode): 0x6c45a2e0
DEBUG:paramiko.transport:Local version/idstring: SSH-2.0-paramiko_2.9.1
DEBUG:paramiko.transport:Remote version/idstring: SSH-2.0-OpenSSH_6.9
INFO:paramiko.transport:Connected (version 2.0, client OpenSSH_6.9)
DEBUG:paramiko.transport:=== Key exchange possibilities ===
DEBUG:paramiko.transport:kex algos: curve25519-sha256@libssh.org, ecdh-sha2-nistp256, ecdh-sha2-nistp384, ecdh-sha2-nistp521, diffie-hellman-group-exchange-sha256, diffie-hellman-group-exchange-sha1, diffie-hellman-group14-sha1, diffie-hellman-group1-sha1
DEBUG:paramiko.transport:server key: ssh-rsa, ssh-dss, ecdsa-sha2-nistp256, ssh-ed25519
DEBUG:paramiko.transport:client encrypt: chacha20-poly1305@openssh.com, aes128-ctr, aes192-ctr, aes256-ctr, aes128-gcm@openssh.com, aes256-gcm@openssh.com, arcfour256, arcfour128, aes128-cbc, 3des-cbc, blowfish-cbc, cast128-cbc, aes192-cbc, aes256-cbc, arcfour, rijndael-cbc@lysator.liu.se
DEBUG:paramiko.transport:server encrypt: chacha20-poly1305@openssh.com, aes128-ctr, aes192-ctr, aes256-ctr, aes128-gcm@openssh.com, aes256-gcm@openssh.com, arcfour256, arcfour128, aes128-cbc, 3des-cbc, blowfish-cbc, cast128-cbc, aes192-cbc, aes256-cbc, arcfour, rijndael-cbc@lysator.liu.se
DEBUG:paramiko.transport:client mac: umac-64-etm@openssh.com, umac-128-etm@openssh.com, hmac-sha2-256-etm@openssh.com, hmac-sha2-512-etm@openssh.com, hmac-sha1-etm@openssh.com, umac-64@openssh.com, umac-128@openssh.com, hmac-sha2-256, hmac-sha2-512, hmac-sha1, hmac-md5-etm@openssh.com, hmac-ripemd160-etm@openssh.com, hmac-sha1-96-etm@openssh.com, hmac-md5-96-etm@openssh.com, hmac-md5, hmac-ripemd160, hmac-ripemd160@openssh.com, hmac-sha1-96, hmac-md5-96
DEBUG:paramiko.transport:server mac: umac-64-etm@openssh.com, umac-128-etm@openssh.com, hmac-sha2-256-etm@openssh.com, hmac-sha2-512-etm@openssh.com, hmac-sha1-etm@openssh.com, umac-64@openssh.com, umac-128@openssh.com, hmac-sha2-256, hmac-sha2-512, hmac-sha1, hmac-md5-etm@openssh.com, hmac-ripemd160-etm@openssh.com, hmac-sha1-96-etm@openssh.com, hmac-md5-96-etm@openssh.com, hmac-md5, hmac-ripemd160, hmac-ripemd160@openssh.com, hmac-sha1-96, hmac-md5-96
DEBUG:paramiko.transport:client compress: none, zlib@openssh.com
DEBUG:paramiko.transport:server compress: none, zlib@openssh.com
DEBUG:paramiko.transport:client lang: <none>
DEBUG:paramiko.transport:server lang: <none>
DEBUG:paramiko.transport:kex follows: False
DEBUG:paramiko.transport:=== Key exchange agreements ===
DEBUG:paramiko.transport:Kex: curve25519-sha256@libssh.org
DEBUG:paramiko.transport:HostKey: ssh-ed25519
DEBUG:paramiko.transport:Cipher: aes128-ctr
DEBUG:paramiko.transport:MAC: hmac-sha2-256
DEBUG:paramiko.transport:Compression: none
DEBUG:paramiko.transport:=== End of kex handshake ===
DEBUG:paramiko.transport:kex engine KexCurve25519 specified hash_algo <built-in function openssl_sha256>
DEBUG:paramiko.transport:Switch to new keys ...
DEBUG:paramiko.transport:Adding ssh-ed25519 host key for 192.168.100.9: b'1c6aaca4a56f19df7bf1d5c00032a6a2'
DEBUG:paramiko.transport:userauth is OK
INFO:paramiko.transport:Authentication (password) successful!
DEBUG:paramiko.transport:[chan 0] Max packet in: 32768 bytes
DEBUG:paramiko.transport:Received global request "hostkeys-00@openssh.com"
DEBUG:paramiko.transport:Rejecting "hostkeys-00@openssh.com" global request from server.
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
DEBUG:paramiko.transport:[chan 0] Sesch channel 0 request ok
DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: Last login: Sat Jan  1 22:57:02 2022 from 192.168.100.27
--- JUNOS 15.1R7.9 built 2018-09-11 05:42:39 UTC


DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 00;9
H
DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 65H


EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: [1
000;97H
EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 1H


EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: [1
000;153H
EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: ;
177H
DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 10
00;233H
EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: ;2
57H
DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 


EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: [10
00;313H
EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 000
;337H
EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 1H

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 417
H

EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: H

EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 00;
473H
EBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: H

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'\n'
DEBUG:netmiko:read_channel: 

DEBUG:netmiko:write_channel: b'set cli screen-width 511\n'
DEBUG:netmiko:Pattern is: Screen width set to
DEBUG:netmiko:_read_channel_expect read_data: set cli screen-width 511

DEBUG:netmiko:_read_channel_expect read_data: root@ex4200-24p:RE:0% 
DEBUG:netmiko:_read_channel_expect read_data: 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
DEBUG:netmiko:_read_channel_expect read_data: 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 

DEBUG:netmiko:_read_channel_expect read_data: root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 

DEBUG:netmiko:_read_channel_expect read_data: root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
DEBUG:netmiko:_read_channel_expect read_data: 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
DEBUG:netmiko:_read_channel_expect read_data: 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 

DEBUG:netmiko:_read_channel_expect read_data: root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 

DEBUG:netmiko:_read_channel_expect read_data: root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 

DEBUG:netmiko:_read_channel_expect read_data: root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
root@ex4200-24p:RE:0% 
DEBUG:netmiko:_read_channel_expect read_data: 
root@ex4200-24p:RE:0% set cli screen-width 511
set: Syntax Error.
root@ex4200-24p:RE:0% 
DEBUG:netmiko:write_channel: b'exit\n'
DEBUG:paramiko.transport:EOF in transport thread

Thanks a lot for any hint ! Vladimir

Issue Analytics

  • State:closed
  • Created 2 years ago
  • Comments:5 (3 by maintainers)

github_iconTop GitHub Comments

1reaction
ktbyerscommented, Jan 4, 2022

I think the issue is that you are logging in with the root account and Netmiko needs to switch to Junos CLI.

And Netmiko needs to execute this:

https://github.com/ktbyers/netmiko/blob/develop/netmiko/juniper/juniper.py#L41

And Netmiko’s code here probably needs improved as I think it fails to enter the Junos CLI properly. So that code probably needs improved. I will flag this as a bug so someone can try to improve this.

0reactions
ktbyerscommented, Apr 14, 2022
Read more comments on GitHub >

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