Master Network Automation with Python for Network Engineers using SSH, Paramiko, Netmiko, Telnet or Serial Connections

Network automation is the process of automating network configuration and management tasks using software tools and scripts. Automation can help network administrators reduce manual errors, improve network performance, and increase efficiency.

To automate network tasks, you need to be familiar with various networking protocols and programming languages. In this response, I will focus on the SSH, Paramiko, Netmiko, Telnet, and serial connections.

SSH:

SSH (Secure Shell) is a network protocol that provides secure access to remote devices. It is widely used in network automation to connect to network devices and execute commands remotely. Here's an example of how to use SSH with Python:

import paramiko

# Define SSH parameters

host = "192.168.1.1"

port = 22

username = "admin"

password = "password"



# Create SSH client

ssh = paramiko.SSHClient()

ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())



# Connect to device

ssh.connect(hostname=host, port=port, username=username, password=password)



# Execute command on device

stdin, stdout, stderr = ssh.exec_command("show interfaces")



# Read command output

output = stdout.read().decode()



# Close SSH connection

ssh.close()

print(output)

Paramiko:

Paramiko is a Python library that provides an interface for working with SSH. It simplifies the process of establishing SSH connections and executing commands on remote devices. Here's an example of how to use Paramiko to execute a command on a remote device:

import paramiko

# Define SSH parameters
host = "192.168.1.1"
port = 22
username = "admin"
password = "password"

# Create SSH client
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())

# Connect to device
ssh.connect(hostname=host, port=port, username=username, password=password)

# Create SSH channel
channel = ssh.invoke_shell()

# Execute command on device
channel.send("show interfaces\n")

# Read command output
output = channel.recv(1024).decode()

# Close SSH connection
ssh.close()

print(output)

Netmiko:

Netmiko is a multi-vendor library that simplifies network automation by providing a consistent interface to various network devices. It supports SSH, Telnet, and serial connections. Here's an example of how to use Netmiko to connect to a Cisco device and execute a command:

from netmiko import ConnectHandler

# Define device parameters
device = {
    "device_type": "cisco_ios",
    "ip": "192.168.1.1",
    "username": "admin",
    "password": "password"
}

# Create Netmiko connection
net_connect = ConnectHandler(**device)

# Execute command on device
output = net_connect.send_command("show interfaces")

# Close Netmiko connection
net_connect.disconnect()

print(output)

Telnet:

Telnet is a network protocol that provides remote access to network devices. It is similar to SSH but is less secure as it sends data in plain text. Here's an example of how to use Telnet with Python:

import telnetlib

# Define Telnet parameters
host = "192.168.1.1"
port = 23
username = "admin"
password = "password"

# Create Telnet connection
tn = telnetlib.Telnet(host, port)

# Login to device
tn.read_until(b"Username: ")
tn.write(username.encode() + b"\n")
tn.read_until(b"Password: ")
tn.write(password.encode() + b"\n")

# Execute command on device
tn.write(b"show interfaces\n")

# Read command output
output = tn.read_until(b">").decode()

# Close Telnet connection
tn.close()

print(output)

Serial:

Serial connections are used to connect to network devices using a serial cable. It is commonly used for console access to network devices. Here's an example of how to use Python to connect to a Cisco device using a serial connection:

import serial

# Define serial parameters
port = "/dev/ttyUSB0" # or "COM1" for Windows
baud_rate = 9600
timeout = 1

# Create serial connection
ser = serial.Serial(port, baud_rate, timeout=timeout)

# Send login credentials to device
ser.write(b"\r\n")
ser.write(b"Username: admin\r\n")
ser.write(b"Password: password\r\n")

# Execute command on device
ser.write(b"show interfaces\r\n")

# Read command output
output = ser.read_until(b"#").decode()

# Close serial connection
ser.close()

print(output)

These code examples demonstrate how to use SSH, Paramiko, Netmiko, Telnet, and serial connections for network automation tasks. Remember to test your scripts in a lab environment before using them in production.