Bygd av en fagperson, med personvern først

Verktøykassen for nettverk og sikkerhet som holder dataene dine på din maskin.

Subnettberegninger, DNS- og e-postdiagnostikk, sertifikatinspeksjon og mye mer, beregnet lokalt i nettleseren din. Ingen opplasting, ingen logging, ingen konto nødvendig for de daglige verktøyene.

Bygd av en som har gjort jobben siden 1996.

Tretti år innen bedriftsnettverk og sikkerhet, levert av en aktiv instruktør og ikke av en markedsføringsside. Sertifisert på plattformer, så sammenligningene her er gjort ærlig, ikke for å selge.

The chapters lived from inside

In every one of these, employer or vendor, the work was the same shape: facing the end customer, in pre-sales and in post-sales technical support, and very often acting as the technical proxy and enablement facilitator for the partners who had to carry the product themselves. The job was to leave the customer with something that worked better than it did before — an innovation, a solution, an improvement they could keep running after I left. The full telling lives at the career record.

Read the career record

Mer om personen bak

Plattformene, undervist og holdt oppdatert.

What is here

Vendor hubs

One door per platform: the tools, articles and certification material for that vendor, gathered in one place.

Tools

Deterministic calculators and explainers for networks, security and identity. They compute in your browser and send nothing anywhere.

152 live

Learn

Technical articles on the protocols and products behind the tools, written to be read rather than skimmed.

553 articles

Glossary

Every term and acronym used across this site, defined once and cross-referenced. The thing to open mid-article.

Industry

Company histories from the beginning of networking to now, including the ones that failed and the ones nobody remembers.

289 companies4 of them turn 50 this year

The Practice

How the work is actually done rather than how the technology works. Triage, escalation, evidence, handover.

64 published

Certification guides

What each exam tests and what to study for it. Free, and useful whether or not you ever book a course.

105 guides

Study guides

Objective-by-objective walkthroughs for the exams, showing what is covered here and, honestly, what is not.

Training I teach

Authorized instructor-led courses across four platforms, delivered through Red Education.

Advisory

Independent judgement on decisions that have not been made yet. Scoped work, written answer, no on-call.

By engagement

About

Who is writing all of this, what I have done, and why any of it should be trusted.

The career record

Fifteen chapters from 1996 onward, each told from inside the company it happened in.

Red Education

The global authorized training centre my courses are delivered through, and the story of how it got there.

Hvorfor lokal kjøring betyr noe i sikkerhetsarbeid.

Når du limer inn en konfigurasjon, et pakkeopptak eller et sertifikat i et verktøy, inneholder disse dataene ofte hemmeligheter. Her kjører de daglige verktøyene helt i nettleseren din. Inndataene forlater aldri enheten din, så det er ingenting å logge, lekke eller utlevere etter en rettskjennelse.

Prøv et verktøy nå.

CIDR-kalkulatoren nedenfor kjører lokalt. Skriv inn et nett og et prefiks for å se adresseområdet, antall verter og masken. Ingenting sendes noe sted.

Åpne hele verktøykassen

CIDR-kalkulator

Analyserer en enkelt IPv4-CIDR-blokk: nett, kringkasting, maske og vertsområde.

Kjører lokalt, ingenting sendes til noen server.