Network and service-provider engineering
BGP, routing policy, peering, transit, RPKI, IPv4/IPv6, IS-IS, OSPF, MPLS, EVPN/VXLAN, incident analysis and the operational design around them.
NETWORK / INFRASTRUCTURE / ROLLOUTS / TEACHING
I go where
the problem is.
From BGP policy to the switch port that is actually flapping.
At 21:00, it was clear that another remote call would not rescue a factory network rollout in northern Czechia.
At 02:00, I was on a bus to the airport. By early afternoon, after Helsinki, Paris, Prague and a train north, I was on site.
Roughly 3,000 kilometres after making the decision, we solved the problem.
20+ YEARShands-on systems and network engineering
17 YEARSbuilding and operating an ISP
EUROPE-WIDErollouts, interventions and multi-site work
DEFINED WORKconsulting, delivery, teaching and handover
01 / WHAT I DO
Useful across the boundaries where projects get stuck.
I am usually brought in when the problem spans more than one supplier, one technical layer or one team. Sometimes the right answer is architecture. Sometimes it is a console cable and another look at the link state.
Access networks and connectivity
Bitstream access, FTTH, DSL, carrier Ethernet, leased lines, CPE, address resources, last-mile migrations and the service models around access products.
European rollouts and site intervention
Planning, staging, supplier coordination, travel, on-site delivery, acceptance testing and handover for offices, factories, datacenters and multi-site environments.
LAN, Wi-Fi and physical infrastructure
Switching, VLANs, PoE, wireless, structured cabling, installation and troubleshooting from the physical link upward. I am not afraid of the part that needs hands.
Systems, datacenter and recovery
Linux and BSD, virtualisation, storage, monitoring, identity, datacenter platforms, migrations and technical recovery when “it must be the network” has stopped helping.
Provisioning, OSS/BSS and automation
Product and service workflows, data models, APIs, inventory, provisioning states and operational tooling built around how a provider actually works.
02 / FIELD NOTES
Two examples of what “get it working” can mean.
FIELD NOTE 01 / INDUSTRIAL ROLLOUT
The remote call had reached its useful limit.
A new industrial site was being brought online. The local team was struggling with the network fabric, and remote assistance was no longer moving the rollout forward.
I decided at 21:00 that the next useful step was to be there. A bus at 02:00, two flights and a train later, I reached the site the following afternoon and worked directly with the team. By the time my colleagues in Turku expected me at the office, I was calling them from Paris.
Result: the issue was resolved, the rollout moved again, and the factory could continue towards production.
TurkuHelsinkiParisPragueNorthern Czechia
FIELD NOTE 02 / OFFICE NETWORK
The firewall problem that was not a firewall problem.
A customer called on Friday. Around 100 SAP consultants were due to move into a new office on Monday. The Wi-Fi was unstable, and there was no useful wired fallback.
The access points worked during testing, then failed after installation. Replacement hardware behaved the same way. Vendor support focused on firewall rules. The useful clue was lower down the stack: PoE remained available while the Ethernet link cycled between down and a negotiated 2.5 Gbit connection.
I changed the Dell PoE switch so that the affected ports advertised only 10, 100 and 1,000 Mbit during link negotiation.
Result: the site became stable.
21:14:08POEpower stable
21:14:09LINKup / 2500M
21:14:13LINKdown
21:14:16LINKup / 2500M
21:14:21LINKdown
21:31:42CONFIGadvertise 10/100/1000
21:31:45LINKup / 1000M / stable
03 / WAYS TO WORK WITH ME
Senior expertise without turning it into another permanent support dependency.
I work alongside existing technical teams, suppliers and local hands. Each engagement has a scope, a commercial agreement, an outcome and a handover.
01
Technical intervention
A defined problem and a concentrated block of work.Diagnosis, implementation, written findings or a clear next decision.02
Rollout or delivery assignment
A site, country or multi-site workstream.Planning, coordination, on-site delivery, acceptance and handover.03
Reserved consulting
Regular scheduled engineering or advisory days.Useful continuity without an open-ended support queue.04
Teaching and speaking
Internal briefings, workshops, classes, conference talks and CTF material.Practical content based on systems that met reality.Short-notice travel is available.
When an agreed engagement genuinely needs somebody on site, I can often move quickly within Europe.
Permanent on-call is not the product.
I do not operate a general end-user support desk or sell unrestricted 24/7 availability.
The commercial side is explicit.
New work normally begins with paid discovery or a prepaid engineering block. Travel and non-refundable external costs are agreed before booking.
I am not positioned as low-cost field labour. Clients bring me in when delay, another failed attempt or the wrong technical decision costs more than senior expertise.
04 / PROVISIONING PLATFORM
Assisted implementation. Operator-owned architecture.
I originally studied application development before changing direction and qualifying in systems engineering. Today I use coding assistants to accelerate implementation, while keeping the architecture, framework choices, data model, integrations and operational workflows under my own direction.
One result is a working provisioning platform designed as a foundation for an OSS/BSS environment. It applies service-provider knowledge built over more than two decades to the software that has to represent products, resources, orders, services and actual network state.
The assistant accelerates code. It does not decide what an access product, address resource, provisioning state or operational handover means.
OPERATOR WORKFLOW
PRODUCTORDERSERVICE
ACCESSRESOURCENETWORK
APIPROVISIONINGOPERATIONS
Framework-aware development around real provider processes, not a generic CRUD demo with telecom labels.
05 / SELECTED WORK
Things with packets, sites, users or consequences.
ISP OPERATIONS
Built and operated an ISP
Seventeen years across backbone routing, peering, transit, access products, addressing, datacenters, monitoring, migrations, provisioning, suppliers and customer escalations.
EUROPE
International rollout and enterprise work
Hands-on and advisory work in offices, factories, datacenters and multi-site environments, from southern France to northern Norway and from Central Europe to Sicily, plus intercontinental assignments.
AS41051
FREETRANSIT
A non-commercial routing project giving students, enthusiasts and emerging networks practical access to BGP and real Internet resources.
Project siteEXERCISES
Locked Shields and Crossed Swords
Worked with the exercise and industry-partner teams on infrastructure, local model-serving systems and operations in 2025.
LOCAL AI
Self-hosted model-serving platform
Operated local inference and model-serving infrastructure for challenge environments and contributed extensively to adversarial testing.
SwiNOG materialRESEARCH SUPPORT
Internet measurement
Provided a small amount of production-routing and infrastructure support to research acknowledged in an ACM IMC 2025 paper.
Paper
LOCKED SHIELDS 2025 / TALLINN / EXERCISE AND INDUSTRY-PARTNER WORK
06 / SECURITY IN PRACTICE
Security from the perspective of somebody who has to operate the system.
My security work grows out of infrastructure: understand how the system actually runs, how people depend on it, and where the assumptions stop holding.
That includes routing security, incident analysis, secure infrastructure, cyber-defence exercise work, local AI systems and adversarial testing.
07 / ABOUT
Built across the stack, comfortable at the edges.
For 17 years I built and operated an ISP and related infrastructure businesses. That meant owning the outcome across routing, access networks, systems, datacenters, suppliers, customer platforms, field work, incidents and the software around them.
I now apply that experience through a smaller independent practice, taking on selected consulting, rollout, teaching and development assignments. Commercial engagements are handled through Openfactory Nordic Oy under the Institute for Pyrotechnical Cleaning name.
I began in application development, changed direction into systems engineering, completed the Swiss federal qualification in computer science, and later taught in Swiss professional and higher technical IT education. I have also worked around startups, Internet exchanges, network-operator communities, international public-sector infrastructure and large multinational enterprises.
Community work includes FREETRANSIT, Internet-exchange involvement, years in the RIPE and hacker communities, and service as a board member of TurkuSec ry.
- 2004–2010
- Apprenticeship and early systems-engineering work. Swiss Federal Certificate of Proficiency in Computer Science completed in 2010.
- 2009–2026
- Built and operated service-provider and managed-infrastructure businesses in Switzerland and Finland.
- 2010s–present
- Teaching and mentoring in Swiss professional and higher technical IT education alongside engineering work.
- Education
- System Engineering, BBW Winterthur. Earlier studies in Application Development.
- Competitions
- Swiss Federal Championship in Computer Science: 3rd place System Engineering in 2007; 5th place in 2008.
- Languages
- German native. English fluent. French technical support. Finnish A2.2 and improving.
BGPIPv6RPKI / ROVASPABITSTREAMFTTH / DSLIS-ISOSPFMPLSEVPN / VXLANLAN / WI-FIPOELINUX / BSDPROXMOX / CEPHDATACENTEROSS / BSSAPISTEACHING
08 / PUBLIC RECORD
Talks, writing, projects and the communities around them.
Operator, security and hacker communities have been part of my working life for a long time. The chronology below links the talks, workshops, writing, projects and events that left a public trace.
SELECTED PUBLIC WORK
Routing incidents, Internet exchanges, RPKI, local AI, homelabs and systems after they met reality.
My public work ranges from BGP workshops and Internet exchanges to production routing incidents, routing security, homelabs and local AI. The chronology also includes the communities around that work.
Advancements in Routing Security on Global Scale
CERT-EE programmeQuestioning the IPv8 Proposal
RIPE Labs articleSelf-hosted LLM challenge infrastructure
SwiNOG #40How we caused a route leak
Disobey talkUsing IXP Manager to run a transit provider
RIPE 87 programmeSecuring your router with RPKI
GPN recording archiveOpen the complete chronology2007–2026
2026
Advancements in Routing Security on Global Scale
Routing-security practice from the operator side: what is deployable now, what is changing, and where the gaps still are.
Programme ↗Questioning the IPv8 Proposal
An operator reading of an ambitious protocol proposal, with rather more questions about deployment and operations than about the slideware.
Read at RIPE Labs ↗RIPE 92
Followed the measurement and routing sessions and asked a few practical operator questions around RPKI data and ASPA. A couple of people joining remotely recognised the voice afterwards.
EVENTS FOSDEM · Brussels · Disobey · Helsinki · Netnod Meeting · Stockholm · Easterhegg · Koblenz · RIPE 92 · Edinburgh · nog.fi · Tampere
2025
Locked Shields + Crossed Swords
Worked with the exercise and industry-partner teams on infrastructure, local model-serving systems and operations.
Supporting Internet-measurement research
Provided a small amount of production-routing and infrastructure support to an Internet-measurement project, acknowledged in the resulting ACM IMC 2025 paper.
Paper ↗How to build and self-host CTF challenges using a language model
A practical local GenAI stack: model serving, self-hosting, hardware constraints and an adversarial challenge environment.
Local AI challenge infrastructure
Operated the self-hosted model-serving platform used for the challenge environment and contributed extensively to adversarial testing.
Easterhegg 2025 ↗Adversarial testing and an occasional AI detox.
Two pieces on adversarial testing and on keeping some deliberate distance from constant AI use.
Let’s break some AI
Hands-on adversarial testing around the local challenge platform.
EVENTS Disobey · Helsinki · Easterhegg · Hamburg · WHY2025 · Netherlands · DENOG17 · Essen · BalCCon · Novi Sad · 39C3 · Hamburg
2024
RIPE meeting
Operator-community discussions, hallway conversations and the usual working-group sessions.
Meeting ↗Disarray2024
A practical talk about building a home lab, using it to experiment with real systems, and why more people should learn by running and breaking their own infrastructure.
Event recap ↗EVENTS Disobey · Helsinki · Disarray · Baltic Sea · DENOG16 · Berlin · BalCCon · Novi Sad · 38C3 · Hamburg
2023
Using IXP Manager to Run a Transit Provider Network
Using exchange-point software in a service-provider network, with the compromises and operational lessons that come with doing that for real.
Programme ↗How we caused a route leak: anatomy of a routing incident
A real route leak, how we got there, what it did, and what changed afterwards.
Little Bobby’s First Bigger Routeleak
A production routing incident, an AS-SET that did not behave as expected, and the post-mortem.
EVENTS RIPE 86 · Rotterdam · RIPE 87 · Rome · Disobey · Helsinki · Easterhegg · Hamburg · DENOG15 · Berlin · Chaos Communication Camp · Mildenberg · 37C3 · Hamburg
2022
Running the camp IXP at MCH2022
Ran the camp IXP at MCH2022 using IXP Manager. The exchange brought together several community networks, including AS41666 and FREETRANSIT / AS41051.
MCH2022 IXP wiki ↗A Story From The Trenches
Operational networking stories from the provider side.
nog.fi meeting ↗OSINT from the perspective of an ISP
A hands-on evening around the information an operator can pull together from an IP address or network: RIR data, BGP, traceroutes, reverse DNS, WHOIS and the surrounding infrastructure.
WireGuard and MikroTik, on actual routers
Hosted a small practical workshop with TurkuSec, building WireGuard setups on MikroTik hardware instead of stopping at a slide deck.
EVENTS MCH2022 · Netherlands · TurkuSec · Turku · BalCCon · Novi Sad
2021
Executive Board candidate
Stood for the RIPE NCC Executive Board with a focus on operator experience, education and bringing more people into the networking community.
2020
EVENTS FOSDEM · Brussels · Disobey · Helsinki
2019
Internet Exchanges and why we need them
Recording archive ↗Securing your Router with RPKI
Recording archive ↗RPKI Validation + BGP Workshop
Programme ↗Traffic Mining: Feel the packets, be the packets
Helped run a hands-on Tranalyzer traffic-mining workshop at the TurkuSec lab, working directly with captured traffic and analysis tooling.
Tranalyzer workshop archive ↗EVENTS Disobey · Helsinki · TurkuSec · Turku · Easterhegg · Vienna · GPN19 · Karlsruhe · BalCCon · Novi Sad · DENOG11 · Hamburg · Chaos Communication Camp · Mildenberg · 36C3 · Leipzig
2018
CHIX: a new Internet Exchange in Switzerland
Programme ↗EVENTS FOSDEM · Brussels · Disobey · Helsinki · Easterhegg · Würzburg · BalCCon · Novi Sad · 35C3 · Leipzig
2017
2016
RFC3021: Why aren’t we using it?
/31 point-to-point networks, sixteen years after the RFC already said we could stop wasting two addresses per link.
Slides ↗EVENTS BalCCon · Novi Sad · 33C3 · Hamburg
2015
South East Europe operator meeting
Meeting ↗EVENTS RIPE SEE 4 · Belgrade · Chaos Communication Camp · Mildenberg · BalCCon · Novi Sad · 32C3 · Hamburg
2014
BGP Routing Workshop
Programme ↗EVENTS BalCCon · Novi Sad · 31C3 · Hamburg
2013
2012
Easterhegg 2012
Worked as an Archangel during the event, helping keep the day-to-day operation of the Easter weekend moving.
Event ↗EVENTS Easterhegg · Basel · 29C3 · Hamburg
2011
RIPE meeting
Meeting ↗EVENTS RIPE 63 · Vienna · Chaos Communication Camp · Finowfurt · 28C3 · Berlin
2010
2009
2008
2007
SwiNOG and the provider community.
Became active in the Swiss network-operator community while still early in my systems-engineering career.
09 / CONTACT
Bring me a problem, a rollout, a class or a CFP link.
Consulting and delivery
Tell me what is happening, what has already been tried, where the work is, who is already involved and what a useful outcome would look like.
I will tell you directly whether I am likely to be useful.
Discuss the workTeaching and speaking
Send the event or organisation, date, audience, topic and CFP link where applicable.
I am quite capable of noticing a CFP shortly after it closes, so a direct nudge is welcome.
Send an invitationEngagements are contracted through Openfactory Nordic Oy, operating under the Institute for Pyrotechnical Cleaning name.