Python for Network Engineers

You already know which parts of your job a computer should be doing.

The interface audit across three hundred switches. The pre-change capture nobody has time for. The inventory spreadsheet another team swears is the source of truth. You have thought "I should learn Python" more than once, opened a tutorial, found yourself sorting a list of fruit, and closed it again.

This book never does that. Every example is network data — show output, interface tables, inventories, IP plans — from the first variable to the concurrency chapter that reaches four hundred devices without waiting four hundred times.

Who this is for

Network engineers who have never programmed. If you can read a running configuration and you know what SSH is, you have the prerequisites. There is no computer science here, and no assumption that you have written code before.

What you will be able to do

•      Install and configure Python properly on Windows, macOS or Linux, including virtual environments and pip — explained, not copy-pasted

•      Read, reshape and write network data: variables, lists, dictionaries, loops, functions, files, CSV, JSON and YAML

•      Connect to devices with Paramiko and Netmiko, parse output with TextFSM instead of fragile regex, and handle the failures that appear at three hundred devices but never at three

•      Ask the same question of Cisco, Juniper and Arista through NAPALM, and reach for Nornir when a for loop stops being enough

•      Talk to controllers and platforms over REST and RESTCONF, and to devices over NETCONF with ncclient

•      Generate configuration from Jinja2 templates, keep a golden configuration, and detect drift before an auditor does

•      Automate the work that never touches a device: inventory reconciliation, IP address maths with ipaddress, Excel reporting with openpyxl, credentials pulled from KeePass

•      Use AI properly — the Claude and OpenAI APIs, a model running on your own machine, and the prompt patterns that produce network scripts worth keeping rather than confident nonsense

•      Put your scripts under version control and test them, so your automation does not become the next outage

What is in the book

•      632 pages, seventeen chapters in five parts, plus three appendices

•      Part I — Getting Set Up. Why Python belongs in your toolkit, installing it on every platform, and the editor, virtual environment and lab you will work in

•      Part II — The Python You Actually Need. Variables, collections, conditionals and loops, functions and modules, files and structured data, and parsing device output

•      Part III — Talking to the Network. SSH with Paramiko and Netmiko, REST and RESTCONF and NETCONF, then NAPALM and Nornir at scale, with concurrency, retries and credential handling done properly

•      Part IV — Templates and Real Use Cases. Jinja2 configuration generation, golden configs and drift detection, and the off-box automation that needs no lab at all

•      Part V — AI and Where to Go Next. AI APIs and local models, prompt patterns for network scripting, version control, testing and where to take it from here

How it is written

Every listing is complete and runnable. Nothing is left as an exercise unless it is meant to be, and the code is commented for someone who has never programmed — but only where something is new, so the listings never turn into noise.

Each chapter ends with Hands-On Practice, and every one of those exercises has a worked solution in Appendix A. There are no quiz questions: this is a course, not a certification guide.

Examples are Cisco-first, with Juniper and Fortinet shown wherever the difference actually matters.

The book also ships with a glossary, a quick reference for Netmiko, NAPALM, Nornir and Jinja2, a full index, and a clickable table of contents in the PDF.