Denis Hierholzer


IT Systems Engineer (Network, Security, Windows and Linux Servers)
Multiple mayor certifications, 15+ years work experience

Table of Content

Quick Intro

Lead Network and Security, Senior Systems Administrator/Engineer with multiple major IT certifications (e.g. MCSA: Windows Server, CEH, LPIC-1 and Cisco Certified Professional) and more than 15 years work experience. Specialized in Windows servers, Active Directory, backup, virtualization, monitoring and deployment. Also interested in Linux, networking, security, software development and scripting. Excellent documentation skills.

Since 2007 I have worked as a Systems Administrator/Engineer, focusing on several topics like Windows servers, Active Directory, backup, virtualization, patch management and monitoring. Beside that I am also working with Linux servers, develop small applications or plugins (Java, C#, Python) and love automating tasks with scripting (Batch, VBS, Powershell, Linux Shell). I'm also experienced in writing detailed technical documentations for administrators and end users. Further education is very important to me that's why I regularly work on certifications and attend IT courses. Furthermore I am proactive, very punctual and highly organized. In my spare time I enjoy extending my own IT infrastructure and explore upcoming applications and services.

Check out my self-developed application PicR (Picture Randomizer) >>

Explore my IT lab >>

Work Experience - After Graduation

IT Infrastructure Engineer
Cilag AG – a Johnson & Johnson company
Schaffhausen, Schaffhausen, Switzerland
March 2021 – now
Engineering and administration of the whole Schaffhausen OT infrastructure (LAN, WLAN, firewalls, Linux and Windows servers, SAN) including but not limited to

  • Active Directory
  • Backup software
  • Cisco ACI
  • PowerShell scripting
  • VMware vSphere

IT Systems Engineer
Syntegon Technology Services AG
Beringen, Schaffhausen, Switzerland
June 2020 – February 2021 (9 months)
Engineering and coordination of multiple infrastructure projects with a focus on networking (WAN, LAN, WLAN, DMZ, firewalls, etc.), automatisation and scripting (Powershell)

Lead Network and Security
former job roles: Infrastructure Analyst / Systems Engineer (June 2014 – Feb 2019)
Schroder & Co Bank AG
Zurich City, Switzerland
June 2014 – May 2020 (6 years)
Employed at the IT Operations department with following responsibilities:

  • Administration and installation of Windows, Solaris, network and security systems
  • Operating of T24 (banking app)
  • VMware infrastructure, vFailover
  • System Center infrastructure (SCCM, SCOM)
  • Security systems implementation & administration (AD RMS, Palo Alto firewall, privileged access management)
  • Process automation (PowerShell)

Senior Systems Administrator / Systems Engineer
Dentsu Holdings USA / 360i – since Jan 2014
New York City, USA
December 2012 – March 2014 (1 year 4 months)
Reference Letter EN
Employed at the corporate IT department managing about 10 branches and more than 300 servers worldwide in a mixed Windows/Linux environment.
Administration and engineering of Windows and Linux servers, VMware vSphere, SCCM, Active Directory, WSUS, McAfee ePO (anti-virus), Redmine, Atlassian JIRA and Confluence, EMC NetWorker, MS Exchange, MS SQL Server (incl. clustering and SQL queries) and Apache Subversion (incl. replication). Developed several PowerShell and VBS apps.

IT Officer
Bomatec AG
Hoeri, Zurich, Switzerland
January 2011 – October 2012 (1 year 10 months)
Reference Letter EN | Reference Letter DE
Recruited to manage all IT related tasks including project management. Scope of position was versatile and included management of:

  • Network Services
  • Windows 7 Desktop Systems
  • Help Desk Operations
  • Newsletter Operations
  • Windows 2008 R2 Servers
  • Exchange 2010 Servers
  • SQL Server
  • Lync 2010 System
  • SAN System
  • Backup System
  • ERP System

Systems Administrator / Systems Engineer
Bucher Hydraulics
Klettgau, Germany
September 2007 – December 2010 (3 years 4 months)
Reference Letter DE
Employed at the central IT department managing 16 branches and about 100 servers worldwide. Administrated the whole Lotus Notes / Domino infrastructure including migration from version 7 to 8. Developed and improved various Notes applications.

Work Experience - Before Graduation

Web Developer (Diplomate)
eschbach IT GmbH
Bad Saeckingen, Germany
March 2007 – August 2007 (6 months)
Diploma Thesis (technologies: PHP, AJAX), Web Development

See accomplishments and projects at eschbach IT GmbH

Systems Administrator (Student Apprentice)
Micronas GmbH
Freiburg, Germany
March 2006 – August 2006 (6 months)
Network Administration, Second Level Support, Server Administration, Scripting

Systems Administrator and First-Level Supporter (Student Apprentice)
HARMAN/BECKER Automotive Systems GmbH
Stuttgart Area, Germany
September 2004 – February 2005 (6 months)
Network Administration, First Level Support, Application Development

Database Developer (Freelance)
Textilbuero Weissenberger GmbH
Klettgau, Germany
August 2002 – September 2002 (2 months)
Database Development (MS Access) for Order Processing

Volunteer Experience

Volunteer Systems & Web Administrator
Gemeindebuecherei Klettgau – Public Library
Klettgau, Germany
January 2002 – July 2020
User Support, System Administration, Website Development and Administration

Certificate about volunteering work

2017-01-15 Report about the official appreciation

See accomplishments and projects at Gemeindebuecherei Klettgau


Diplom-Informatiker (FH) – BSc-equivalent
Hochschule Furtwangen University
Field of Study: Computer Networking
Grade: 1,8 (equivalent to A-)
2003 – 2007 (4 years)

List of all attended study subjects >>

Abitur – German High School (-Level) Diploma
Gewerbliche Schulen Waldshut – Informationstechnisches Gymnasium
Heavy focus on IT
Grade: 1,9 (equivalent to A-)
2000 – 2003 (3 years)


Fitnesstrainer B-Lizenz
May 2024

Cisco Certified Specialist – Enterprise Core
Certificate Verification No: W4NVKKSPCCQQQ6W2
Passed CCNP-Switch (300-115) in April 2019 and CCNP-Route (300-101) in July 2019
July 2019

LPIC-1: Linux Administrator
November 2018

Check Point Certified Administrator (CCSA) – R80
August 2018

Palo Alto Networks ACE (Accredited Configuration Engineer) – PAN-OS 7.0
February 2017

Cisco Certified Network Associate – Security (CCNA-Security)
Certificate / NSA INFOSEC – 4011 Recognition
Exam IINS (210-260)
November 2016 (valid until July 2022)

EC-Council – Certified Ethical Hacker (CEH)
Certificate | Verify Certificate
Exam 312-50 (v9), Certification Number: ECC99079878168
April 2016 (valid until April 2025)

Oracle Certified Associate, Oracle Solaris 11 System Administrator
Exam 1Z0-821
November 2015

Intensivkurs Bankfach Basis (finance business fundamentals)
Fachschule fuer Bankwirtschaft
September 2014 – January 2015

Cisco Certified Network Associate – Routing and Switching (CCNA R/S)
Exam ICND2 v2.0 (200-101)
December 2013 (valid until July 2022)

Cisco Certified Entry Networking Technician (CCENT)
Exam ICND1 v2.0 (100-101)
November 2013 (valid until July 2022)

VMware Certified Associate – Data Center Virtualization (VCA-DCV)
Exam VCAD510
November 2013

Microsoft Certified Solutions Associate – Windows Server 2008 (MCSA)
May 2012

Microsoft Certified IT Professional – Server Administrator (MCITP:SA)
May 2012

IBM Certified System Administrator – Lotus Notes and Domino 8.5
August 2010

Cambridge Certificate in Advanced English (C1 Level)
University of Cambridge, License 0026114096
December 2009

IBM Certified System Administrator – Lotus Notes and Domino 8.0
October 2009

IHK Certified Data Protection Officer (dt.: Datenschutzbeauftragter)
September 2008

Independent Coursework

First Aid Course / Erste Hilfe Ausbildung fuer betriebliche Ersthelfer
Certificate of Completion
November 2021

Red Hat Ansible for Network Automation (DO457)
Certificate of Completion
November 2021

immocation Masterclass – “Vermoegensaufbau mit Immobilien”
Certificate of Completion
August 2019 – January 2020

Check Point Certified Security Expert R80.20 (CCSE-CP R80.20)
Certificate of Completion
January 2020

Management Essentials Training
2 days on-site workshop, webinar, virtual workshop
- Identity shift and adaptability
- Managing change and performance through coaching
- Building effective relationships
September 2019

Cisco ROUTE-1.0 – Implementing Cisco IP Routing (ROUTE)
Certificate of Completion
June 2019

Cisco SWITCH-2.0 – Implementing Cisco IP Switched Networks (SWITCH)
Certificate of Completion
March 2019

Check Point Cyber Security Administrator R80.10 (CCSA-CP R80.10)
Certificate of Completion
May 2018

Tanium 7 Foundation, Operations, & IR Deep Dive
Certificate of Completion
Course Description
November 2017

Palo Alto Networks – Firewall: Install, Configure, and Manage (EDU-201)
Certificate of Completion
February 2017

PowerShell for the IT Administrator – Part 2 (Microsoft WorkshopPLUS)
Certificate of Attendance
January 2014

PowerShell for the IT Administrator – Part 1 (Microsoft WorkshopPLUS)
Certificate of Attendance
July 2013

Microsoft SQL Server 2008 Administration Course (VTC)
Course Details
March 2013

Planning, Deploying and Managing Microsoft SCCM 2007 (MOC 6451)
Certificate of Attendance
June 2011

Two-Day-Course “OpaccOne for System Administrators” (ERP-System)
Certificate of Attendance
May 2011

One-Day-Course MS Office 2010
Certificate of Attendance
April 2011


English – Full professional proficiency

German – Native speaker

Swiss German – Native speaker

French – Basic knowledge

Personal Commitment

Organizer of the New York City German Culture Meetup Group
2013 – 2014

Student President at the IT Faculty
Hochschule Furtwangen University
2005 – 2006

Preferred Work Location

My preferred work location is within a radius of about 50 km of 79771 Klettgau, Germany. Please see the map below to get a better idea of this area.

Preferred Work Location

Preferred Work Location