Q:

SSH protocol banner

Working with Netmiko library in python to automate Cisco login via SSH proxycommand, while executing the script it returns ssh protocol banner issue, 
been trying to identify this issue for a week now but no luck so far.
Destination host : Linux
Netmiko version :2.3.3
Paramiko:2.5.0
SSH Proxy Configuration ( ( ~/.ssh/config)
host jump
hostname 172.16.1.10
IdentitiesOnly yes

host 192.168.1.10
ProxyCommand ssh jump nc %h %p

python Script :
#!/usr/bin/env python

from netmiko import ConnectHandler
import paramiko

device = {
   'device_type': 'linux',
   'host': '192.168.1.10',
   'username': 'testuser',
   'password': 'Password',
   'ssh_config_file': '~/.ssh/config',
}
   net_connect = ConnectHandler(**device)
   output1 = net_connect.send_command('uname -a')
   print output1

Error :
No handlers could be found for logger "paramiko.transport"
Traceback (most recent call last):
File "Python_Scripts/connection.py", line 12, in <module>
net_connect = ConnectHandler(**device)
File "/usr/lib/python2.7/site-packages/netmiko/ssh_dispatcher.py", line         228, in ConnectHandler
return ConnectionClass(*args, **kwargs)
File "/usr/lib/python2.7/site-packages/netmiko/base_connection.py", line 312, in __init__
self.establish_connection()
File "/usr/lib/python2.7/site-packages/netmiko/base_connection.py", line 858, in establish_connection
self.remote_conn_pre.connect(**ssh_connect_params)
File "/usr/lib/python2.7/site-packages/paramiko/client.py", line 397, in connect
t.start_client(timeout=timeout)
File "/usr/lib/python2.7/site-packages/paramiko/transport.py", line 601, in start_client
raise e

paramiko.ssh_exception.SSHException: Error reading SSH protocol banner

A:

I think this is probably related to this issue:
https://github.com/ktbyers/netmiko/issues/1259
If your device is very slow for some reason and doesn't respond in a reasonable time (by respond I mean present the SSH banner), then Paramiko will raise an error.
We are probably going to wire in the Paramiko's banner_timeout argument shortly so you can increase this timeout in Netmiko.

