Python für Netzwerkautomatisierung

Python for Network Automation

Introducing Paramiko

Paramiko: Basic SSH Connection

import paramiko

def connect_and_run(hostname, username, password, command):
    client = paramiko.SSHClient()
    client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    
    try:
        client.connect(hostname=hostname, username=username, password=password, timeout=5)
        stdin, stdout, stderr = client.exec_command(command)
        print(f"Output:\n{stdout.read().decode().strip()}")
        print(f"Errors:\n{stderr.read().decode().strip()}")
    except paramiko.AuthenticationException:
        print("Authentication failed, please check your credentials.")
    except paramiko.SSHException as e:
        print(f"SSH connection error: {e}")
    except Exception as e:
        print(f"An error occurred: {e}")
    finally:
        client.close()

if __name__ == "__main__":
    # Replace with your actual server details and command
    HOST = "your_server_ip"
    USER = "your_username"
    PASS = "your_password"
    CMD = "echo Hello from Paramiko!"
    
    print("Attempting to connect with Paramiko...")
    connect_and_run(HOST, USER, PASS, CMD)
    print("Note: This code won't connect without a live server and valid credentials.")

Handling Command Output

Paramiko for File Transfers (SFTP)

Introducing Netmiko

Netmiko: Connect to Network Devices

from netmiko import ConnectHandler

def connect_with_netmiko(device_info):
    try:
        print(f"Attempting to connect to {device_info['host']} with Netmiko...")
        net_connect = ConnectHandler(**device_info)
        print(f"Successfully connected to {net_connect.base_prompt}")
        net_connect.disconnect()
        print("Disconnected from device.")
    except Exception as e:
        print(f"Netmiko connection error: {e}")

if __name__ == "__main__":
    # Replace with your actual device details
    device = {
        "device_type": "cisco_ios", # e.g., cisco_ios, juniper_junos, etc.
        "host": "your_device_ip",
        "username": "your_username",
        "password": "your_password",
        "secret": "your_enable_secret" # Optional, for enable mode
    }
    
    connect_with_netmiko(device)
    print("Note: This code won't connect without a live device and valid credentials.")

Netmiko: Sending Configuration

from netmiko import ConnectHandler

def send_config_to_device(device_info, config_commands):
    try:
        print(f"Connecting to {device_info['host']} to send config...")
        net_connect = ConnectHandler(**device_info)
        
        print("Sending configuration commands...")
        output = net_connect.send_config_set(config_commands)
        print(f"Configuration Output:\n{output}")
        
        net_connect.disconnect()
        print("Disconnected.")
    except Exception as e:
        print(f"Netmiko config error: {e}")

if __name__ == "__main__":
    # Replace with your actual device details
    device = {
        "device_type": "cisco_ios",
        "host": "your_device_ip",
        "username": "your_username",
        "password": "your_password",
        "secret": "your_enable_secret"
    }
    
    # Example configuration commands
    config_lines = [
        "hostname CoddyRouter",
        "no ip domain lookup",
        "line vty 0 4",
        "login local"
    ]
    
    send_config_to_device(device, config_lines)
    print("Note: This code won't apply config without a live device and valid credentials.")

Best Practices & Security

Paramiko vs. Netmiko

Recap: Python for Net Automation