From symptom to root cause.
Each write-up follows one structure: overview, problem, investigation, root cause, resolution, verification and lessons. A fix is only called completed when it was actually tested.
A /8 route that swallowed cloud traffic
Users at several sites could not reach some cloud applications and popular websites, while everything else worked.
Read case study · 4 minBandwidth numbers that disagreed
Usage graphs from different layers of the stack disagreed, so none could be trusted for reporting.
Read case study · 3 minThe disk that was quietly dying
A production gateway showed a bad sector on /dev/sda and very high power-on hours.
Which IPs are actually free?
I needed the free versus used addresses in a /24 client network without reading a session list by eye.
Read case study · 2 minThe switch that refused to speak Ansible
The standard Ansible IOS modules failed against a Cisco Small Business switch.
Read case study · 3 minEvery write-up reads the same way.
- Overview and problem. What was wrong and what it affected.
- Investigation. Commands, logs and observations.
- Root cause. What the evidence actually established.
- Resolution and verification. The change and the proof.
- Lessons learned. What I would do differently.
Let's talk about your network.
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