Linux · mail · RF — Stockholm, SE
Systems administrator and operations engineer with ten years in Linux environments. At Saab I run the group's mail platform — flow, delivery, authentication and the security wrapped around it — and I'm dragging encrypted communications and network services onto something more modern. Good ops is the kind nobody ever hears about.
About me
I'm a systems administrator and operations engineer, and a decade in now — a NOC floor, private clouds, a hospital being wired up, and today group IT in the defence sector. The thread through all of it is the same: make the service boring, make the failure loud, and keep the runbook short enough that somebody actually reads it.
Most of my attention these days is on email: mail flow, delivery, filtering and the authentication trinity of SPF, DKIM and DMARC, plus the encrypted communications and network services I'm migrating off legacy stacks. Before that, at Exicom, it meant ISO 27001-aligned routines, hardening baselines, a password manager and TOTP for everyone — security that survived contact with a real workplace.
Off the clock it's radio and RF: SDR-based signal geolocation, security analysis of LoRa mesh protocols, satellite contacts via QO-100, and hardware for security conferences. I sit on the board of SK0QO, was on AMPRNet Stockholm for 2024–2025, volunteer as an operator at Tekniska museet, and teach soldering at SEC-T and Security Fest — which is a bracing way to find out whether a badge design works under pressure.
Toolkit
Currently learning: fine-tuning small models on hardware I own, more about AMPRNet routing, and how to explain the 40 m band to non-hams.
Journey
Run Linux environments across group IT, remotely. The core of it is the mail platform: flow, delivery, authentication and security end to end — SPF, DKIM, DMARC, filtering, and the eternal argument about where the spam line actually sits. Alongside that I'm migrating encrypted communications and network services to more modern replacements.
Full-time responsibility for Linux operations. Drove ISO 27001-aligned security standards through the workplace and rolled out the things that make an audit quiet: password management, server hardening baselines and TOTP for everyone.
Five months in Linux environments with observability and development — metrics, automation, and finding out where a system actually hurts rather than where the dashboard is prettiest.
Three months building new private cloud environments and keeping hardware and software alive, both on-site and in the cloud. Short engagement, lots of platforms in a small amount of time.
Two and a half years in a Network Operations Center: Linux operations, monitoring, backup and maintenance. Where I learned that an alert nobody can act on is worse than no alert at all.
Started in IT support for Stockholm County Council and got moved on-site to New Karolinska Solna, helping build up the hospital's IT infrastructure — Windows Server, clients and networking, in a building that could not afford a bad day.
Electronics design, networking and computer science — plus an amateur radio licence in 2014, call sign SA0CVK, which turned out to be the more useful of the two.
Selected work
An independent security comparison of two LoRa mesh protocols: routing behaviour, cryptography including known CVEs, jamming resilience and the governance model behind each. Written because "it's encrypted" is not an argument.
Read the analysisBadges and tooling for SEC-T and Security Fest: a Python Meshtastic notifier that announces pretalx sessions before and after they start, a uConsole receiver for the public LoRa channel, and badge hardware and firmware on ESP32, RP2040, CH32V003 and ATtiny — LED matrices and audio included. The 2025 Security Fest badge took two days, after the original designer walked past the deadline.
See the codeA Prometheus exporter that publishes delay data from Stockholm's SL bus traffic, so the commute can be graphed and alerted on instead of merely resented. Small, boring, and exactly the kind of thing that should already exist.
SourceBeyond the keyboard
SA0CVK. SDR and RF security work on an Ettus B210 and a KrakenSDR: signal geolocation, drone-signal monitoring, and contacts via QO-100. Also designed a battery and audio board for the QRP Labs QMX+ and gave the design away to the community.
I teach soldering at SEC-T and Security Fest, and build the hardware and simpler design work for both. Forty minutes, a hot iron and a room full of sceptics is the most honest design review there is.
Language models on hardware I own with llama.cpp: picking models and quantisations to fit a memory budget, benchmarking the box, agentic tool use, and training or fine-tuning small models of my own.
Board member of SK0QO, AMPRNet Stockholm 2024–2025, and an operator at Tekniska museet — the Swedish National Museum of Science and Technology.
Contact
Assignments and consulting in Linux operations, email infrastructure, hardening and observability — or a good-natured argument about LoRa mesh security, SDR and soldering. In Swedish or in English.