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Infrastructure

Self-Hosted & Self-Managed

Running since 2016. Dell VRTX chassis with three M630 blade servers, Cisco C2960S switching, ISR 1900 router, WLC with Aironet APs. 8 VLANs. Fully automated via Ansible.

Homelab — rack servers, Cisco AP, networking gear
The Lab
Dell VRTX · 3x M630 Blades · Cisco C2960S · ISR 1900 · WLC + Aironet APs · 8 VLANs · Running since 2016
Dell VRTX VMware ESXi Cisco IOS Ansible Docker Caddy WireGuard Debian 12
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Expertise

Technical Skills

Full-stack engineering with a focus on backend systems, DevOps, and security.

Work

Featured Projects

Open-source tools and production systems I've built and maintain.

Writing

Latest from the Blog

Technical deep-dives on infrastructure, security, and systems. Live from blog.c0xl.ch.

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Interactive

Talk to my Server

Type help to explore. Full command history, autocomplete, and pipe support.

christian@c0xl — zsh
christian@c0xl:~$
Lifetime

Career in Numbers

Approximate stats since age 12. Some of these are real. Some are suspiciously accurate.

OS Installs — The Journey
47
Debian 8 Jessie
the golden era
31
Debian 9 Stretch
systemd was new
23
Debian 10 Buster
learning phase over
18
Debian 11 Bullseye
fewer reinstalls = growth
38
Debian 12 Bookworm
the daily driver
21
Debian 13 Trixie
testing branch, living dangerously
15
Ubuntu Server
then switched to Debian
8
Arch Linux
btw
4
FreeBSD
jails before Docker was cool
2
macOS
for the M-series hardware
Infrastructure
342
VMs destroyed
they had it coming
8,412
Docker containers started
docker ps -a | wc -l
890
Cisco configs pasted
copy run start
0
SSL certs manually renewed
thanks Caddy
14
Uptime records broken
then the PSU died
0
Cables managed
see homelab photo
Developer Life
6,200
Hours in Vim
still can't exit
48,000+
:wq typed
muscle memory
7
git push --force
all forgiven
3
rm -rf near-misses
we don't talk about #2
412
"works on my machine"
it did tho
0
Production databases dropped
not even once
Lifetime Counters
0
Cups of coffee
runs on pure willpower
75+
Certifications earned
continuous learning
14
Years on Linux
since 2012, no regrets
207
Total OS installs
and still counting
2,847
Stack Overflow visits
without an account
1
ThinkPad fan controllers written
in C, obviously
Dedication

Commit Activity

Live from GitHub. Every green square is a day I shipped code.

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Security

What Your Browser Leaks

This is what any website can see about you right now — no cookies, no login, just your browser. Think about that.

VISITOR RECON — PASSIVE SCAN SCANNING...
Gathering data...
Activity

Recent GitHub Activity

Live from the GitHub Events API.

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Connect

Let's Build Something

Available for opportunities, consulting, and interesting conversations about infrastructure and security.

@ christian.lehnert@tutanota.com >_ GitHub in LinkedIn ● Status Page