Doorway 02 · Engineering & Code

Twenty years of keeping
large systems honest.

Network automation, Linux, Python, open source, and the slow craft of running infrastructure at scale. An archive that starts in 2009 and spans certs, scripts, essays on practice, and the occasional rant about how software eats the network.

2026

Controlling APC PDUs with a Nautobot Job

Three Ways to Leverage AI for Code Development

2025

Understanding Dataloaders in AI: What They Are and Why They Matter

25 Years of U.S. Oil Dynamics: A Deep Dive into Production, Consumption, and Trade

PCAP or It Didnt Happen

What Are Tokenizers in AI, and Why Are They Important?

2024

Hierarchical Configuration Version 3

2023

Predicting Future Internet Capacity Needs Using Time Series Data

Extracting Specific Key-Value Pairs from a List of Dictionaries in Ansible

2022

RHCSA Version 8: Operating Running Systems

RHCSA Version 8: Getting Started

2020

2019: Year in Diving

2016

A New Approach to Defending Against DDoS Attacks

Network Lifecycle Management with Hierarchical Configuration

Multi Change and Netlib Updates

Kicking the tires on the new Ansible Network Modules, Part 2

Kicking the tires with the new Ansible Network Modules

NANOG 66

Using a serial console on Mac OS X

Using Ansible to update your Home Dynamic DNS via Rackspace Cloud DNS

2015

Using Ansible to PUSH Cisco IOS Configurations

pyMultiChange rewrite and Netlib

Dockerizing IOS-XRv

Troubleshooting Internet Connectivity

pyMultiChange and pyRouterLib Updates

2014

MPLS Control and Data Plane Cheat Sheet

Cisco VIRL - Bare Metal Install Tips and Lessons Learned

Cisco VIRL Status? Digital Paper Weight

The Irony of Using SDN and NFV to Study Legacy Network Technologies

Mental Note: Tracking L3 Glean Attacks

pyMultiChange - SSH Script Update

Updated pyRouterLib and pyMultiChange

Python with Multiple Threads

Connecting Your Virtual IOS-XE and IOX-XR Lab To Your Physical Lab

Working with Cisco Routers and Switches with Python

Dynamic DNS Updates via the Rackspace Cloud DNS

Updating my Python Scripts to access Cisco Devices

Linux Unified Key Setup

OSPF Area Types and LSA's

IOS-XR (XRv) and IOS-XE (CSR1000v) KVM Config Generation

CCNP - Service Provider - SPROUTE

TelnetCisco.py - A Reusable Module for Accessing Cisco Devices with Python

Quick intro to Puppet

2013

I'm going to place these here...

DMVPN with VRF's for the Internet interfaces and BGP

Rackspace Performance vs Standard Cloud Server Disk I/O

Managing Cisco Routers / Switches with Python, Take 2

Configuring Cisco routers and switches with Python

BGP Goodness and Links

Google Chromecast and scanning for WiFi Networks

Performing a full system restore after a Linux server re-kick

Introduction to MPLS

SDN Goodness

SELinux For Mere Mortals

Cisco Zone Based Firewall and UDP based Traceroute

Filesystem I/O Speeds Benchmarking Perl Script

Learning Python

Bash - Random Password Changer

Bash Shell Enumerator - Command Not Found

Quick one-liner to change all databases tables to InnoDB in MySQL.

OpenNHRP RPM Updated

Linux File Server for Apple Time Machine Backups

Rackspace Private Cloud Edition - Compute Setup

Rackspace Cloud Servers and Networks with Open vSwitch and VXLAN between Data Centers

2012

Playing with Openvswitch.

The Nerdiest IPv6 related domain name on the Internet

IPv6 Subnetting

IPv4 Subnetting Made Easy

SELinux - Listing Available Contexts