NAPALM gives network engineers one Python API across Cisco, Arista, and Juniper — normalized getters plus config diff, commit, and rollback for safe multi-vendor automation.
Netmiko makes router SSH automation easy: send_command with TextFSM parsing, send_config_set for changes, save_config, enable mode, and fleet-wide pushes with error isolation.
Drive a real SSH session to a router from Python with Paramiko — exec_command vs invoke_shell, disabling paging, handling auth failures, and a reusable connect-and-run helper.
Build a TCP port reachability checker with Python's socket module — connect_ex, timeouts, DNS resolution, and a management-plane service audit across a device list.
Run ping, traceroute, and nslookup from Python with subprocess.run — capture output, check return codes, set timeouts, and avoid shell-injection bugs.
Use Python's re module to pull IPs, MACs, interface counters, and BGP states out of show command output — with named groups and the metacharacters that cover most network parsing.
Python's built-in ipaddress module handles subnets, host iteration, overlap detection, and subnetting for network engineers — no pip install required.
A complete, device-agnostic walkthrough for building a road-warrior OpenVPN server on an OPNsense firewall (running on a Zimaboard), then connecting iPhone, Android, MacBook, Windows, and Linux clients to your home network.
Day 7 closes Week 1 of the Python for Network Engineers series. Read and write files cleanly with `with`, catch only the exceptions you mean, and use the standard logging module so your scripts leave a real paper trail.
Day 6 of the Python for Network Engineers series. Define functions, use *args/**kwargs the way Netmiko expects, write your first reusable module, and learn the __name__ == '__main__' guard.