2022 Update: If you want a clear technical explanation of the OSI model, click on the cover of my book CCNP Enterprise Certification Study Guide: Implementing and Operating Cisco Enterprise Network Core Technologies for a free preview of Chapter 1 which explains each layer of the OSI model in intricate detail. I …

After years of manually upgrading my self-hosted WordPress installation, I decided it was finally time to apply some devops principles (namely automation) to this process. I decided to use AWS Systems Manager (aka SSM). I started out by creating the following Command Document (which happens to be in YAML format because …

If you’ve ever created a private hosted zone in Route 53, you may have noticed it always assigns the same name servers: 1 ns-1536.awsdns-00.co.uk. 2 ns-0.awsdns-00.com. 3 ns-1024.awsdns-00.org. 4 ns-512.awsdns-00.net. The numbers don’t seem to be coincidental. 1536 is the RFC number for “Common DNS Implementation …