Netmiko and NAPALM

Netmiko and NAPALM are two of the most widely used Python libraries for network automation. Netmiko simplifies SSH connections to network devices, while NAPALM provides a unified, vendor-agnostic API for configuration management and operational data retrieval.

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Netmiko

What is Netmiko?

Netmiko is a multi-vendor SSH library built on top of Paramiko. It handles the painful details of interacting with network device CLIs:

Feature	Description
Auto-detection of device type	Identifies prompts and adjusts behaviour
Handles pagination	Automatically sends terminal length 0 or equivalent
Enter enable mode	enable() method with password support
Enter config mode	config_mode() enters and exit_config_mode() leaves
Structured output	Integrates with TextFSM for parsed results
Multi-vendor	Supports 60+ device types (Cisco IOS/XE/XR/NXOS, Arista, Juniper, etc.)

Installation

pip install netmiko

Supported Device Types (Selection)

Device Type String	Platform
cisco_ios	Cisco IOS / IOS XE
cisco_nxos	Cisco NX-OS
cisco_xr	Cisco IOS XR
arista_eos	Arista EOS
juniper_junos	Juniper Junos
paloalto_panos	Palo Alto PAN-OS
linux	Linux servers

Basic Usage

from netmiko import ConnectHandler

device = {
    "device_type": "cisco_ios",
    "host": "192.168.1.1",
    "username": "admin",
    "password": "secret",
    "secret": "enable_password",  # Enable password
}

with ConnectHandler(**device) as conn:
    # Enter enable mode
    conn.enable()

    # Send a show command
    output = conn.send_command("show ip interface brief")
    print(output)

Sending Configuration Commands

from netmiko import ConnectHandler

device = {
    "device_type": "cisco_ios",
    "host": "192.168.1.1",
    "username": "admin",
    "password": "secret",
}

config_commands = [
    "interface GigabitEthernet0/1",
    "description Uplink to Core",
    "ip address 10.0.0.1 255.255.255.252",
    "no shutdown",
]

with ConnectHandler(**device) as conn:
    output = conn.send_config_set(config_commands)
    print(output)

    # Save the configuration
    conn.save_config()

Structured Output with TextFSM

from netmiko import ConnectHandler

device = {
    "device_type": "cisco_ios",
    "host": "192.168.1.1",
    "username": "admin",
    "password": "secret",
}

with ConnectHandler(**device) as conn:
    # Raw text output
    raw = conn.send_command("show ip interface brief")
    print(type(raw))  # <class 'str'>

    # Structured output using TextFSM
    structured = conn.send_command("show ip interface brief", use_textfsm=True)
    print(type(structured))  # <class 'list'>

    for intf in structured:
        print(f"{intf['intf']}: {intf['ipaddr']} ({intf['status']})")

Automating Multiple Devices

from netmiko import ConnectHandler
from concurrent.futures import ThreadPoolExecutor

devices = [
    {"device_type": "cisco_ios", "host": "192.168.1.1", "username": "admin", "password": "secret"},
    {"device_type": "cisco_ios", "host": "192.168.1.2", "username": "admin", "password": "secret"},
    {"device_type": "arista_eos", "host": "192.168.1.3", "username": "admin", "password": "secret"},
]

def get_version(device: dict) -> str:
    with ConnectHandler(**device) as conn:
        return conn.send_command("show version")

# Run in parallel using threads
with ThreadPoolExecutor(max_workers=5) as executor:
    results = executor.map(get_version, devices)

for device, result in zip(devices, results):
    print(f"--- {device['host']} ---")
    print(result[:200])  # First 200 characters

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NAPALM

What is NAPALM?

NAPALM (Network Automation and Programmability Abstraction Layer with Multivendor support) provides a unified Python API across different network vendors. Instead of writing vendor-specific commands, you use the same methods regardless of the device type: