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Daniel Pepuho
Daniel Pepuho

Posted on • Updated on

How to solve 'authentication failed' in Paramiko

I got an error when running automation script for network device like this:

~python-Automation/ $ python3 multivendor.py 

Traceback (most recent call last):
  File "multivendor.py", line 23, in <module>
paramiko.ssh_exception.AuthenticationException: Authentication failed.

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so when you have entered the correct password and username but still get an error like that, you need to add this parameter in your automation script

look_for_keys=False
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finally, the parameter will disable search for discoverable private key files in ~/.ssh/.

so you will see my script like this

import paramiko
import time

devices = [
    {
        'ip_address' : '172.16.1.1',
        'vendor' : 'mikrotik',
        'username' : 'router1',
        'password' : 'tes'
    },
    {
        'ip_address' : '172.16.1.2',
        'vendor' : 'cisco',
        'username' : 'cisco',
        'password' : 'cisco'
    }
]

ssh_client = paramiko.SSHClient()
ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())

for device in devices:
    ssh_client.connect(hostname=device['ip_address'],
                                username=device['username'],
                                password=device['password'],
                                look_for_keys=False)

    print("success login to {}".format(device['ip_address']))

    if device['vendor'] == 'cisco':
        conn = ssh_client.invoke_shell()

        # conn.send("enable\n")
        conn.send("conf t\n")
        conn.send("int lo99\n")
        conn.send("ip add 10.1.99.1 255.255.255.255\n")
        time.sleep(2)

        # output = conn.recv(65535)
        # print(output.decode())
    else:
        ssh_client.exec_command('interface bridge add name=loopback3\n')
        ssh_client.exec_command('ip add add address=10.2.99.2/32 interface=loopback3')

ssh_client.close

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Good luck 😄

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