Python for Network Automation: Netmiko and NAPALM in Practice

Python is essential for the modern network engineer. Netmiko (multi-vendor SSH), NAPALM (unified API), PyEZ (Juniper), and Nornir (Pythonic framework) replace Perl/Expect/Bash. This guide covers the Python network engineering ecosystem in 2026.

Core libraries

Netmiko

• Simple multi-vendor SSH connectivity
• from netmiko import ConnectHandler
• device = { 'device_type': 'cisco_ios', 'host': '10.0.0.1', 'username': 'admin', 'password': 'pass' }
• conn = ConnectHandler(**device)
• output = conn.send_command('show version')

NAPALM

• Unified cross-vendor API
• from napalm import get_network_driver
• driver = get_network_driver('ios')
• dev = driver('10.0.0.1', 'admin', 'pass')
• dev.open()
• facts = dev.get_facts()
• interfaces = dev.get_interfaces_ip()
• dev.close()

PyEZ (Juniper)

• Native Juniper NETCONF/YANG support
• from jnpr.junos import Device
• dev = Device(host='10.0.0.1', user='admin', password='pass')
• dev.open()
• dev.rpc.get_config()

Nornir

• Pythonic framework for large-scale automation
• Hierarchical inventory (vs plain Ansible)
• Native Python parallelization
• Plugins: NAPALM, Netmiko, Jinja2
• Better suited than Ansible for >1000 devices

Requests + REST

• For modern APIs: Meraki, FortiGate, Panorama
• import requests
• r = requests.get('https://api.meraki.com/api/v1/organizations', headers={'X-Cisco-Meraki-API-Key': 'KEY'})

Scapy: packet manipulation

• Craft, send, and capture packets
• Use cases: testing, scanning, and learning
• Example: send a custom ping or test an ACL

Jinja2: templates

• Generate configurations from data
• Integrated with Ansible and also available standalone
• Example: Jinja2 template + YAML → 100 switch configurations

Common use cases

• Configuration backups: Netmiko + cron
• Configuration audits (compliance)
• Dynamic inventory: SNMP scanning + CMDB
• Mass configuration deployment: VLAN, ACL, QoS
• Health checks: post-change validation
• Reports: BGP and OSPF status, CPU, and memory

Tools and IDEs

• VSCode + Python extension
• PyCharm
• Jupyter notebooks for exploration
• Black: formatter
• pylint: linter

Recommended skills

• Python basics: dictionaries, lists, functions, classes
• asyncio: parallel execution
• Git + Gitflow
• REST API + JSON
• Regex for parsing CLI output
• YAML + Jinja2

Training

• Cisco DevNet Associate / Professional
• Python Network Programming (Eric Chou)
• NetworkToCode training courses
• Udemy: Python courses for network engineers
• YouTube: Kirk Byers (Netmiko creator)

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