Since 2017
Writing
The plan says what should happen. This is what I found when I went and looked.
AI, cloud architecture, entrepreneurship, leadership, networking, healthcare, and the place where technology, business, and faith meet. Below is a curated selection carried over from the site I wrote between 2017 and 2020: the case studies and articles the rest of this site is built on. Work published by AWS is listed on About.
2026
2019
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May 9, 2019
Imprints
Article
Two worn spots on a pillow, pressed in by the same two small heads over months. We leave imprints on people whether or not we intend to.
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Apr 19, 2019
Clear CloudFlare Cache from Lambda
Note
Purging a CDN cache on every deploy, with the API key in Parameter Store rather than in the function, because that one key opened most of the account.
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Mar 15, 2019
Case Study: SMTP Limits
Case study
Mail stopped after exactly three messages, repeatably. The firewall never saw the SYN. Every component the customer managed was clean, which left one nobody owned.
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Jan 1, 2019
Relentless
Article
Amazon was almost called Relentless: showing no abatement of severity, intensity, strength or pace. A better description of a working rhythm than of a personality.
2018
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Nov 2, 2018
CloudShark 2018 Halloween Challenge
Case study
CloudShark hid a puzzle inside a packet capture. Carving the objects back out of it and following the conversation until the answer fell out.
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Aug 25, 2018
Case Study: Out of Memory
Case study
A website went down weekly and a reboot always fixed it. I am a network person, so I looked at the network. It was a 1 GB instance with no swap file.
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Jul 7, 2018
Diagram Your Service
Method
You cannot choose a capture point until you understand the service, and the fastest way to understand one is to draw it. The drawing is the diagnosis, not documentation.
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Jul 3, 2018
Command For Dozing
Note
A Cat D11T bulldozer in Arizona, driven live from a trade-show floor in Málaga. Five thousand miles between an operator's hands and several hundred tonnes of moving steel.
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Jun 2, 2018
Case of an FQDN Issue
Case study
"I can't access my shared drive." The finger pointed at the network, as it does. An unfiltered capture caught two packets that were not part of the conversation.
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May 25, 2018
Thoughts from behind a mower
Article
My dad taught me that straight rows come from watching the end of the row, not the ground in front of the blade. It works for architecture and careers too.
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Mar 21, 2018
Case of the Large Header
Case study
The HTTP spec sets no header limit. Every server, proxy and load balancer in the path does, and none of them logged it.
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Feb 1, 2018
Case of the Named Pipes
Case study
"The network path was not found." Vague errors blame the network. This one blamed the network and meant something else entirely.
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Jan 1, 2018
Case of the Tired Firewall
Case study
Unreproducible symptoms, no root cause. The device in the path was not failing; it was tired, and its own health checks were never going to say so.
2017
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Nov 10, 2017
Case of the Rogue Server
Case study
Several hundred users lost connectivity one by one while every device reported healthy. Clearing the ARP table helped for a moment, the only real clue in the incident.
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Sep 23, 2017
Case Study: Capture at Both Ends
Case study
A client sent a TLS 1.2 Client Hello. The server received TLS 1.0. Neither capture alone could have told you that.
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Aug 25, 2017
TCP Performance Options
Method
Window scaling, MSS, Nagle, congestion control. The options every application performance question eventually bottoms out in, and what each one costs you.
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Jun 30, 2017
Performing a Capture
Playbook
You picked the point and set the filters. Now start it, generate the traffic that reproduces the problem, and stop before the evidence buries itself.
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May 28, 2017
Preparing for the Capture
Playbook
Where to capture, how, and what to filter: the prep work that decides whether an analysis is possible at all.
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Apr 8, 2017
Capturing Light
Method
Electricity, light and radio become ones and zeros become packets. How you catch the fastest thing there is, at an exact point, repeatably.
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Mar 10, 2017
Classic Performance Example
Case study
A transfer running at 80 Mbps on a 10 Gbps link, weeks instead of days. Thirty zero window segments in a few seconds said the problem was not the network.
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Feb 22, 2017
IPv6
Note
My ISP had no native IPv6, so I tunnelled it and then captured the traffic to see whether the performance benefits everyone claims for it actually showed up.
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Feb 7, 2017
Online Privacy
Article
A former FBI investigator spoofed the guest wifi and harvested phones in a room full of IT professionals. What I changed about my own data afterwards.