Thomas Joos · IT Consulting & Author
Over 30 years of consulting practice, in parallel more than 100 specialist books and thousands of articles. Consulting clients benefit from constant engagement with the latest technologies , in my own lab, independent of vendor interests.
Currently writing for Amnesty InternationalAutomated filters delete evidence of war crimes
Podcast
I host the podcast and videocast series Insider Research. These are the current episodes.
Watch the episodeInsider Research
Live from Digital X 2026 in Cologne
Networks and security belong together. The conversation covers what companies have to protect once AI systems work inside the network.
with Dr. Niklas Horstmann, COO Telekom SecurityHost Thomas Joos
Watch the episodeOn strategic projects, I support clients from planning through technical implementation to operational security. In the cloud space, my work focuses primarily on Microsoft Azure and AWS. In IT security, the emphasis is on zero-trust architectures and identity access management, complemented by securing OT and production networks along the Purdue model and IEC 62443. For AI projects, my priority is clean integration into existing business processes, not showcases. Further focus areas include resilience consulting, AI-assisted protection against attacks, support during ransomware incidents and the hardening of Azure, Microsoft 365 and Active Directory.
Security consulting often deals with situations where time is the deciding factor. Advisory work during active cyber and ransomware incidents, building resilient IT structures, strategic guidance on cyber defence. This includes classifying AI-assisted code analysis, which now finds vulnerabilities faster than attackers can exploit them. Whether recovery succeeds and the business keeps running rarely depends on the moment of attack. It depends on the years before.
As a permanent trainer at LinkedIn Learning, I regularly produce courses on cloud, IT security and AI, along with video training on Windows Server and storage. The content reaches an international audience and ranges from administrators to IT leadership.
When writing, I move between my own books, articles in the major IT media such as c't, iX, Computerwoche, dpa, PC Welt/World and international outlets, and commissioned work for communications and publishing agencies. Some pieces appear under the names of executives and industry figures whom I support as a ghostwriter.
Consulting clients since 1992
Plus consulting mandates with several state governments and KRITIS operators – treated confidentially, no further details listed here.
Featured in leading IT media
Live feed with the most recent publications
What clients, editors and readers say about the collaboration and the books.
Within the scope of our global migration project, we came to know Mr Thomas Joos as a highly competent, reliable and methodically rigorous partner. In this complex project, more than 3000 mailboxes in numerous countries were migrated to several centrally operated Exchange servers. Thomas Joos optimally solved the complex migration project with his expertise and innovative power, showing great commitment. Another key advantage is the flexibility of the consultant, who supported us quickly and competently around the clock.
I am happy to pass on the feedback from One Identity PR, the senior marketing manager and above all the EMEA Field Marketing team, which uses the publications Europe-wide. Everyone is thrilled with the contributions, especially the latest strategic article that just appeared on Security-Insider.
I read the Security-Insider news regularly. The Patch-Tuesday summary is informative, alarming and reassuring at the same time. The information is correct and important, and the summary is simply brilliant.
That was a great help! Thank you.
In the course of our project we got to know Thomas Joos as a highly competent, reliable and flexible service provider who supported us around the clock. During the migration, all mailboxes from our sites were migrated to a Windows Exchange cluster. In addition, Thomas Joos excellently solved the integration of our mobile clients with Exchange. With his methodical and secure approach, his expertise and his innovative power, he optimally completed the complex migration project with great commitment.
Quite simply THE PERFECT book on its subject. Not a word too many, not one too few. I work in IT professionally, and the current edition of this book has been on my shelf for years. In my opinion, THE STANDARD REFERENCE on this topic.
The article on SR Linux is excellent.
A big thank you for your excellent work.
I always read your iX articles with great benefit – the Proxmox pieces have stuck with me in particular.
Many thanks for the great interview last week! We are delighted that you will turn it into an interview piece.
I really like your new topic suggestions.
A special thank-you for your outstanding, always reliable, fast and above all competent work over all these years – thank you so much!
I'm usually sparing with praise, but the article is well written, I feel understood – and I have nothing to criticise.
The questions look wonderful and fit perfectly. I think the article ideas are great, too.
Admins find help in Thomas Joos's hefty tome, which covers practically every facet of Microsoft's current server operating system.
Your many years of expertise and your well-founded role as a specialist author and consultant in cloud-native transformation and cyber resilience are impressive.
I think the idea and the structure of the webinars are very well done. The last webinar was very well received.
You not only know Synology inside out, your articles are always close to the problems and the solutions of the IT world.
Thank you for the open and genuinely exciting conversation. Your hands-on approach to AI in everyday administration fits very well with what we are looking for.
Thank you for the pleasant collaboration.
Within the scope of our global migration project, we came to know Mr Thomas Joos as a highly competent, reliable and methodically rigorous partner. In this complex project, more than 3000 mailboxes in numerous countries were migrated to several centrally operated Exchange servers. Thomas Joos optimally solved the complex migration project with his expertise and innovative power, showing great commitment. Another key advantage is the flexibility of the consultant, who supported us quickly and competently around the clock.
I am happy to pass on the feedback from One Identity PR, the senior marketing manager and above all the EMEA Field Marketing team, which uses the publications Europe-wide. Everyone is thrilled with the contributions, especially the latest strategic article that just appeared on Security-Insider.
I read the Security-Insider news regularly. The Patch-Tuesday summary is informative, alarming and reassuring at the same time. The information is correct and important, and the summary is simply brilliant.
That was a great help! Thank you.
In the course of our project we got to know Thomas Joos as a highly competent, reliable and flexible service provider who supported us around the clock. During the migration, all mailboxes from our sites were migrated to a Windows Exchange cluster. In addition, Thomas Joos excellently solved the integration of our mobile clients with Exchange. With his methodical and secure approach, his expertise and his innovative power, he optimally completed the complex migration project with great commitment.
Quite simply THE PERFECT book on its subject. Not a word too many, not one too few. I work in IT professionally, and the current edition of this book has been on my shelf for years. In my opinion, THE STANDARD REFERENCE on this topic.
The article on SR Linux is excellent.
A big thank you for your excellent work.
I always read your iX articles with great benefit – the Proxmox pieces have stuck with me in particular.
Many thanks for the great interview last week! We are delighted that you will turn it into an interview piece.
I really like your new topic suggestions.
A special thank-you for your outstanding, always reliable, fast and above all competent work over all these years – thank you so much!
I'm usually sparing with praise, but the article is well written, I feel understood – and I have nothing to criticise.
The questions look wonderful and fit perfectly. I think the article ideas are great, too.
Admins find help in Thomas Joos's hefty tome, which covers practically every facet of Microsoft's current server operating system.
Your many years of expertise and your well-founded role as a specialist author and consultant in cloud-native transformation and cyber resilience are impressive.
I think the idea and the structure of the webinars are very well done. The last webinar was very well received.
You not only know Synology inside out, your articles are always close to the problems and the solutions of the IT world.
Thank you for the open and genuinely exciting conversation. Your hands-on approach to AI in everyday administration fits very well with what we are looking for.
Thank you for the pleasant collaboration.
We chose Thomas Joos because this service provider convinced us with a very high level of technical expertise, a pragmatic approach, geographical proximity, fast response times and communication, as well as an excellent price-performance ratio.
I have already received really good feedback internally. Peter is enthusiastic about the title and management is too.
Thank you so much for the help in resetting my PC after that destructive update. Games no longer worked at all. Not a single one! Now it works again and I am extremely happy.
Compliments on your tips, highly recommended!
After our last audit it was clear that we needed to significantly catch up on hardening our Active Directory infrastructure. With Thomas Joos we made measurable progress in a KRITIS-compliant manner. Above all, the methodical approach and the documentation level convinced our compliance team.
A polished and engaging article on data protection in Google Gemini.
Many thanks for the great webinar. There were many participants with an average attendance time of 32 minutes. Interest was high, and the questions and feedback were very engaging.
A truly excellent lead article on metasurfaces. Engaging topic, concise presentation of the studies.
The Kontron piece is exactly the right format for us.
Peter Schmitz, Editor-in-Chief at Security-Insider, likes the texts – no changes needed. Thanks for handling it so quickly.
Well done – thanks for the excellent work!
Fantastic, the article already looks very good – many thanks for delivering it so promptly!
We only corrected a few small technical details – otherwise we are very happy with the text.
I really liked the text – it contains great, very hands-on tips for the readers.
One of the few books that explains all the important topics in full detail and gives practical step-by-step instructions.
Your profile and your many years of experience as an IT author are very impressive.
Your impressive portfolio, in particular your work for Microsoft Press and the Heise media, along with your long-standing work as a consultant at strategic level, is well known to us and enjoys the highest recognition in our editorial team.
On first skimming I already noticed your cross-reference to the motto of the issue. How elegant!
I like the article a lot. (originally in German)
We chose Thomas Joos because this service provider convinced us with a very high level of technical expertise, a pragmatic approach, geographical proximity, fast response times and communication, as well as an excellent price-performance ratio.
I have already received really good feedback internally. Peter is enthusiastic about the title and management is too.
Thank you so much for the help in resetting my PC after that destructive update. Games no longer worked at all. Not a single one! Now it works again and I am extremely happy.
Compliments on your tips, highly recommended!
After our last audit it was clear that we needed to significantly catch up on hardening our Active Directory infrastructure. With Thomas Joos we made measurable progress in a KRITIS-compliant manner. Above all, the methodical approach and the documentation level convinced our compliance team.
A polished and engaging article on data protection in Google Gemini.
Many thanks for the great webinar. There were many participants with an average attendance time of 32 minutes. Interest was high, and the questions and feedback were very engaging.
A truly excellent lead article on metasurfaces. Engaging topic, concise presentation of the studies.
The Kontron piece is exactly the right format for us.
Peter Schmitz, Editor-in-Chief at Security-Insider, likes the texts – no changes needed. Thanks for handling it so quickly.
Well done – thanks for the excellent work!
Fantastic, the article already looks very good – many thanks for delivering it so promptly!
We only corrected a few small technical details – otherwise we are very happy with the text.
I really liked the text – it contains great, very hands-on tips for the readers.
One of the few books that explains all the important topics in full detail and gives practical step-by-step instructions.
Your profile and your many years of experience as an IT author are very impressive.
Your impressive portfolio, in particular your work for Microsoft Press and the Heise media, along with your long-standing work as a consultant at strategic level, is well known to us and enjoys the highest recognition in our editorial team.
On first skimming I already noticed your cross-reference to the motto of the issue. How elegant!
I like the article a lot. (originally in German)
The book "Windows Server 2022" is one of the most comprehensive Windows Server books on the market. Thomas Joos, a leading authority in this field, delivers another instructive and informative title that can be used as a reference work by beginners as well as experienced Windows Server administrators.
Your articles are among the most-read on the entire site. First of all, I would like to praise you for your Patch-Tuesday reports. The 39 articles I have published from you this year have together generated an enormous number of page impressions. That is an outstanding result, for which I give you great praise and thanks.
Looks great.
Thank you again for the very informative conversation, which we all enjoyed very much and which also inspired us.
When migrating our hybrid Exchange environment to Microsoft 365, Mr Joos did not just deliver the technical concept. Equally important for us was that he clearly worked out the regulatory implications of Schrems-II for our cloud architecture. The combination of both levels was decisive for us.
The approval for your specialist article for our client Kontron has now reached us. Many thanks for the pleasant collaboration! We look forward to the next article assignment with you.
Fantastic! The article looks excellent. Many thanks for the timely submission.
You can tell you engaged deeply with the topic – a strong piece of writing.
You produced excellent practice-oriented articles for us on Kontron in the retail sector, as Jan Lauer reported to me – pieces that were even partly placed via you.
I got in touch with you through my colleague, who already works with you and recommended you to me warmly.
Great article on Updowntool!
Many thanks for the article – excellent as always.
We are convinced your talk is a perfect fit for our event with 140 public-sector clients – we've already heard many good things about you.
It's a pleasure to be in touch with you, and I look forward to working together on future projects.
A good handbook for experienced administrators – the chapters are well and clearly structured, and the balance of screenshots and text is spot on.
I find your interview really very good, and it makes you want to read the facts in the article.
From my point of view, your CV is as impressive as your list of publications. Your clear, reader-friendly writing suits me as well.
One can see immediately that you know the practice side very well. That is excellent!
Thank you for the pleasant collaboration, I am already looking forward to your next article. (originally in German)
The book "Windows Server 2022" is one of the most comprehensive Windows Server books on the market. Thomas Joos, a leading authority in this field, delivers another instructive and informative title that can be used as a reference work by beginners as well as experienced Windows Server administrators.
Your articles are among the most-read on the entire site. First of all, I would like to praise you for your Patch-Tuesday reports. The 39 articles I have published from you this year have together generated an enormous number of page impressions. That is an outstanding result, for which I give you great praise and thanks.
Looks great.
Thank you again for the very informative conversation, which we all enjoyed very much and which also inspired us.
When migrating our hybrid Exchange environment to Microsoft 365, Mr Joos did not just deliver the technical concept. Equally important for us was that he clearly worked out the regulatory implications of Schrems-II for our cloud architecture. The combination of both levels was decisive for us.
The approval for your specialist article for our client Kontron has now reached us. Many thanks for the pleasant collaboration! We look forward to the next article assignment with you.
Fantastic! The article looks excellent. Many thanks for the timely submission.
You can tell you engaged deeply with the topic – a strong piece of writing.
You produced excellent practice-oriented articles for us on Kontron in the retail sector, as Jan Lauer reported to me – pieces that were even partly placed via you.
I got in touch with you through my colleague, who already works with you and recommended you to me warmly.
Great article on Updowntool!
Many thanks for the article – excellent as always.
We are convinced your talk is a perfect fit for our event with 140 public-sector clients – we've already heard many good things about you.
It's a pleasure to be in touch with you, and I look forward to working together on future projects.
A good handbook for experienced administrators – the chapters are well and clearly structured, and the balance of screenshots and text is spot on.
I find your interview really very good, and it makes you want to read the facts in the article.
From my point of view, your CV is as impressive as your list of publications. Your clear, reader-friendly writing suits me as well.
One can see immediately that you know the practice side very well. That is excellent!
Thank you for the pleasant collaboration, I am already looking forward to your next article. (originally in German)
My fields of work in the IT industry.
I write articles and analyses for leading media such as c't, iX, Computerwoche, PC Welt and dpa, as well as for security publications like kes, ComputerWeekly and Security-Insider.
Learn moreI write technical books for renowned publishers. My portfolio includes more than 100 publications with several standard references, including current titles on Windows Server 2025 and Exchange Server SE at O’Reilly and dpunkt.
Learn moreI support companies, KRITIS operators and public authorities up to ministry level in IT strategy, OT security, AI-assisted cyber defence and sovereign cloud.
Learn moreI share my knowledge in video trainings for LinkedIn Learning as well as in lectures on OT security, AI cyber defence and multi-agent AI.
Learn moreNew handbooks at dpunkt and O’Reilly, 2025 and 2026.
Many enquiries begin in a similar way. Here are some situations where I help. An initial conversation is free and non-binding, and on request I then support the technical implementation.
An audit is coming up and it is unclear whether Active Directory and the permission structures will hold. I provide an overview of the critical points and name first measures. On request I support the hardening up to the audit.
A migration to Microsoft 365, Exchange or the cloud is imminent and dependence on a single vendor should stay limited. I classify the architecture options and outline a migration path. If needed, I take on the technical support.
A deadline from NIS2 or DORA is approaching and the scope of action is not yet defined. I clarify what the regulation concretely means for your environment and prioritise the next steps. I support the implementation on request.
An AI project is to start without giving up data sovereignty. I assess the options from local models to the data foundation and name the pitfalls. I help technically with the rollout.
The next technology topic often runs in my own lab before it reaches the market. My current focus is agentic AI. I test Claude Cowork in the Microsoft environment for automating workflows in Outlook and Microsoft 365, and OpenClaw for maximum automation of autonomous agents. Added to this are vulnerability scanning in codebases with Claude Security, delegated managed service accounts in Windows Server 2025 and immutable backups with Object Lock.
Expand your expertise with my most popular video courses on server infrastructure, AI and security.
Lernen Sie, wie Sie ein Synology-NAS professionell für Unternehmensnetzwerke nutzen und absichern.
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Fundiertes Wissen zur Administration, Bereitstellung und Konfiguration von Windows Server 2025.
Bereiten Sie Ihren Tenant auf Copilot vor: Lizenzierung, Berechtigungen, Datenschutz und Rollout.
Der umfassende Grundkurs zur Bereitstellung, Verwaltung und Wartung von Windows Server 2022.
As an independent IT consultant, enterprise architect and technical author, I have been supporting companies, KRITIS operators, OT operators and public authorities for over three decades in the strategic planning, implementation and protection of demanding IT and production infrastructures.
My consulting focus is on cloud architectures in Microsoft Azure and AWS, IT security based on zero-trust principles with identity access management, and the integration of AI into existing business processes. This also covers securing OT and production networks along the Purdue model and IEC 62443. In security consulting, it includes emergency response during active cyber and ransomware incidents, the development of resilient IT structures, classifying AI-assisted code analysis and strategic guidance on cyber defence.
Clients range from mid-sized companies to large enterprises and hyperscalers, including Microsoft, HPE, AWS and Google, for whom I work as a consultant and whitepaper author. In parallel, I advise at ministerial level for several state governments and take on international projects across EMEA and the Middle East.
With more than a hundred technical books, a permanent trainer role at LinkedIn Learning and regular contributions to the largest German-language IT media, I am one of the most-read IT authors in the DACH region. My articles appear in c't, iX, Computerwoche, PC-Welt, kes, ComputerWeekly and Security-Insider as well as through dpa.
In addition, I take on commissioned work for communications and publishing agencies and act as a ghostwriter, producing technical articles for executives and industry figures who publish them under their own name.
Whether strategic consulting, whitepaper, conference talk or workshop – let me know in which context you need support. First conversations are free of charge and non-binding.
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