Network Access Control Experts in Germany

• Functional management and further development of a team of 28 IT employees (internal & external) in the areas of HelpDesk / HelpLine, RHEL (Red Hat), MUREX (trading system & applications), SAP basic operations
• Management of external service providers (including FI-TS for SAP basic operations)
• Personnel, resource and budget planning for the IT department and projects
• Introduction and establishment of regular communication formats (regular meetings, team and cross-departmental meetings)
• Ensuring application operations in a hybrid environment (Windows / Linux with database and web/application servers)
• Support for transformation projects to modernize the application landscape (e.g. DevOps approaches)
• Building and introducing digital IT procurement for hardware & software (e.g. with DELL)
• Development and management of the „IT Operations DOS" department based on the company strategy
• Preparation of management reports & decision papers on IT projects, optimization potential and automation opportunities
• Representing the department in Rentenbank committees and ensuring regulatory compliance (BaFin §44, DSGVO, BSI, MaRisk)

As part of this project, the existing active network infrastructure was modernized and made fit for the future. The goal was to introduce a powerful, secure and scalable network and WLAN infrastructure, including a Network Access Control (NAC) solution to improve network security and centralized access control.

At the beginning of the project, a comprehensive requirements analysis was carried out, taking into account the technical, operational and security-related requirements of the hospital sites. On this basis, a technical tender was prepared for new switches, WLAN access points and the NAC solution.

The successful implementation of the project established a modern, standardized and secure network infrastructure that meets the growing requirements for availability, mobility and IT security in hospital operations.

Activities:

• Supporting the tender process, including technical evaluation of offers and bidder evaluation
• Leading and managing the entire project implementation
• Coordinating the project process with internal stakeholders, business units and hospital IT
• Managing external service providers during the implementation and installation of the systems
• Monitoring the implementation, including quality control, project acceptance and defect management
• Coordinating and managing communication between hospital IT and external service providers as part of the NAC implementation
• Managing escalations in the event of technical and organizational challenges
• Ongoing budget monitoring and control of project expenses and additional costs
• Preparing decision papers for management on project changes, additional services and risks

• Management of firewalls (Securepoint)
• Operation and maintenance of the client-server infrastructure (Windows)
• Operation and patching of IoT devices in the hazard management system (cameras, Web IOS, IP-to-serial converters)
• Support with the integration of security technology into existing IT infrastructures
• Planning and implementation of network segmentation and separation
• Transfer and implementation of solutions in other plants
• Tools used: Wireshark, Network Service Manager, PRTG, Cisco Catalyst, Nexus, HP Service, FNT/Command Manager Console, Service Now, Confluence, Active Directory, Wingard, Securepoint FW.

• Gathering information
• Creating rollout wave concepts
• Coordinating employees
• Monitoring and managing activities
• Project management including analysis and reporting to the board
• Creating instructions and specifications
• Training floorwalkers
• Supporting the rollout on site
• VIP support
• Introducing SharePoint

• Conceptual consulting for securing business processes
• Consulting for planning and implementing IT and IT security projects
• Security and policy checks, process optimization, contingency planning
• Project management and interim management in IT infrastructure and information security

Overview of relevant projects:

• 2025: Consulting on a DLP concept and for Digid GmbH.
• 2025: Consulting for a customer after a cybersecurity attack in which the IT infrastructure was compromised and the attacker gained M365 tenant admin rights. Investigation and recovery of the IT infrastructure. Preparation of recommendations for increasing IT security.
• 2025: Continuation of the projects listed below for Thyssenkrupp Marine Systems and Norddeutsche Landesbank.
• 2024: Preparation of a DNS concept including consulting on DNS strategy and technology, DNS design, DNS security, load balancing, reverse lookup zones and automation. Preparation of a DHCP concept including consulting on DHCP design, the central DHCP management system and automation. Consulting on the operation of the products mentioned, operating processes, and adapting the IT documentation and IT service description for Thyssenkrupp Marine Systems.
• 2024: Analysis and assessment of the network and security infrastructure established by the providers with regard to the overall architecture, consisting of the design and components. Development of proposed solutions to improve current operations, maximize performance and security, and reduce complexity. Presentation of the results, their causes and possible solutions to C-level management, including the required decision templates. Development of a SASE concept based on a Zero Trust architecture for Norddeutsche Landesbank.
• 2024: Continuation of the projects listed below for Atlas GmbH and Deutsche Vermögensberatung AG.
• 2023: Consulting on resolving findings from an IT security assessment of the IT infrastructure, conducting proof-of-concepts for DDoS protection and Digital Experience Monitoring (DEM) with Zscaler (ZIA, ZPA & ZDX), creating a new security architecture based on Zero Trust, redesigning a Cisco ISE implementation and designing a DNS security solution to protect guests and financial advisors for Atlas GmbH / Deutsche Vermögensberatung AG.
• 2023: Continuation of the projects listed below for Digid GmbH, Vaillant Group GmbH (until 09/2023), Bundesanstalt für Geowissenschaften und Rohstoffe (until 05/2023) and Union Investment IT-Services GmbH (until 07/2023).
• 2022: Preparation and review of white papers for infrastructure and security architectures, planning new network infrastructures for Deutsches Luft- und Raumfahrtzentrum.
• 2022: Development of a concept for the technical and process-related modernization of a disaster recovery plan for United Nations Volunteers.
• 2022: Development of a concept for moving measurement data to a cloud environment, introducing Network Access Control and conducting an awareness training session for Digid GmbH.
• 2022: Development of a network segmentation concept for DZ Hyp AG.
• 2022: Development of a network segmentation concept for Bundesagentur für Arbeit.
• 2021: Development of a new load balancer architecture for Bundeswehr Fuhrparkservices GmbH.
• 2021: Vulnerability scan and penetration test of a web frontend, including evaluation and preparation of recommendations for remediation, taking risk and probability of occurrence into account, for customer ifi GmbH.
• 2021: Consulting, concept development and sub-project management for introducing a Network Access Control solution (certificate authentication and MAC address bypass) and macro-segmentation (area and zone concept based on dynamic assignment of endpoints) in office and production IT for customer Vaillant Group GmbH.
• 2021: Upgrade and optimization of the LAN and WLAN infrastructure for customer United Nations Volunteers.
• 2021: Development of a target concept for modernizing the IT security infrastructure consisting of the DMZ (Cisco switches, firewalls, WSA, ESA, SMA), internet access, admin and management networks and wireless LAN, including support during implementation, for Bundesanstalt für Geowissenschaften und Rohstoffe.
• 2021: Creation of a micro-segmentation concept based on Cisco DNA and SGT and Zero Trust for Union Investment IT-Services GmbH.
• 2021: Review and update of ISMS Level-3 policies and preparation of process instructions for customer Software AG.
• 2021: Project management for the global Tec-Refresh project Meraki WLAN 2.0, coordination of outsourcing the LAN/WLAN infrastructure to a managed service provider and preparation of a WLAN concept for automated guided vehicles for customer Heraeus Infosystems GmbH.
• 2021: Project management and technical support for the “Transition of SIEM/SOC Services” project of a customer into a shared environment and assumption of the interim role of Head of Security Operations at customer Datagroup SE.
• 2021: Workshop for a future implementation of Mobile Device Management at customer Allgeier Experts Go GmbH.
• 2021: Sub-project management for introducing a rule management tool for firewalls and recertifying NAC endpoints based on 802.1x and MAB at customer Union Investment IT-Services GmbH.
• 2020: Development of a network segmentation concept for two data centers based on Cisco and VMware for Aareon AG.
• Recording and analysis of the current network architecture, including project initiation.
• Development of a concept for micro-segmentation in the data center and access network.
• 2020: Infrastructure and security architecture audit for customer Stuttgarter Versicherung AG.
• Analysis of the IT infrastructure and IT security architecture with regard to the configuration of network and security components. Additional review of contracts, process descriptions and manuals for completeness. Development of recommendations to improve the stability and operation of the infrastructure. Preparation of a network segmentation concept and project management for implementing the measures from the analysis project.
• 2020: Consulting on setting up an ISMS-Light for customer Josera foodforplanet GmbH & Co. KG.
• 2020: Security architecture consulting for customer Datagroup SE.
• Development of a future IT infrastructure and IT security architecture.
• Analysis of the current IT architecture of all 23 companies.
• Recommendations for optimizing the IT infrastructure and preparation of a comparison between a classic perimeter security concept and the Zero Trust model.
• Preparation of a security zone concept.
• Preparation of an IT infrastructure architecture in coordination with all companies.
• 2018 - 2019: Stream Lead in the Cyber Security program of Deutsche Lufthansa AG.
• Responsible for designing and implementing 9 projects in IT security infrastructure and user access management, as well as managing project managers and experts.
• Project area: Network Segmentation and Access Control.
• Project area: Security Architecture.
• Project area: Privileged, Identity & Access Management.
• Project area: Simplify User Authentication (MFA).
• Project area: Mobile & Endpoint Security.
• Project area: OT Security.
• Project area: E-enabled Aircraft.
• 2018: Security architecture consulting for customer Deutsche Lufthansa AG.
• Project management for the development, evaluation and management of the company-wide information security architecture.
• Development of a security strategy and roadmap to align the security architecture with the Zero Trust model.
• Evaluation of security solutions, services and tools available on the market.
• Definition of requirements for RfPs and evaluation of offers.
• Development, maintenance and monitoring of security architecture artifacts.
• Conducting security assessments of existing and new IT systems and security services.
• 2018: ISMS consulting for customer GLS IT Services GmbH.
• Consulting on introducing and initially operating an ISMS based on ISO27001.
• Auditing the IT environments of the GLS country companies.
• Analysis and assessment of IT security risks and derivation of required measures.
• Development of proposed solutions in coordination with the relevant stakeholders.
• Project management and transition of the ISMS to later operations.
• 2016 - 2018: Security Pre-Sales Consultant for customer Cisco Systems GmbH.
• Nationwide strategic and conceptual consulting for major enterprise customers and financial and insurance customers on Cisco and Meraki security products and services such as Firepower, WSA, ESA, Stealthwatch and ISE.
• 2017 - 2018: Design and implementation of an ISMS for customer Verivox GmbH.
• Conducting various BIAs and GAP analyses.
• Preparation of security policies based on ISO 2700x.
• Assumption of the interim role of Information Security Officer.
• 2017: Preparation of a contingency concept for VPV Lebensversicherungs-AG.
• Review and update of the IT contingency manual.
• 2016: Consulting and project management for the design of cloud and hosting services for customer Vodafone Group Services GmbH.
• Analysis and optimization of the sell-build-run process.
• Preparation of detailed-level designs for cloud products.

• Operational management of a hybrid Palo Alto Networks firewall infrastructure in an IoT environment
• Network zoning using VLANs
• Analysis, optimization, and security hardening of the rule set
• Implementation of additional firewalls in the infrastructure
• IP address management
• Security operations for Nozomi Networks’ IoT NRD solution
• Security operations for secXtreme’s honeypot infrastructure
• Managing service providers to ensure and implement required network measures
• Communication with customers and service providers in an international environment
• Technologies used: Palo Alto Networks, Panorama, Palo Alto AWS-cloud-Firewall, Nozomi Networks, Honeybox

• As-is assessment of the current network infrastructure and its documentation, including on-site inspections
• Independent planning of new distribution and main distribution rooms in the individual district offices (components used, rack layout, connectivity), considering the BSI IT-Grundschutz and InfoSic requirements
• Planning of new copper and fiber optic cabling, including patch panels
• Coordination with building services engineering (TGA) to ensure compliance with relevant on-site requirements
• Development of detailed execution plans and high-level concepts for the rollout of the new infrastructure
• Additional support after the components go live (hypercare phase)
• Regular communication with project management and client stakeholders

• Responsible for the configuration, maintenance, monitoring, troubleshooting, and optimization of the IT infrastructure, including Extreme Networks, SD-WAN, and Fortinet security solutions, at all international company locations in Europe and North America
• Development of a comprehensive strategic roadmap to optimize the network architecture, including VLANS, NAC, QoS, firewall configurations, VPNs, DPI, NGFW, threat intelligence, and SSL/TLS inspection
• Implementation of the OneIT strategy through the introduction of new technologies such as Cisco DNA Center, ExtremeCloud IQ, FortiOS, FortiManager, and FortiAnalyzer, which increased employee skills and the efficiency of the IT systems
• Integration of IT and OT systems to optimize the network and security architecture and improve operational efficiency

• Successfully certified as Professional Scrum Master (PSM I)
• Further training in AI trends, prompt engineering, and tools (ComfyUI, SD3.5, Flux, Loras)
• Market analysis for the strategic realignment of the service portfolio

I implemented a Zero-Trust architecture for robust, military-grade maritime container mini data centers based on VMware & Tanzu to support containerized GIS workloads for ground forces. The main focus was on securing communications, workload protection, and data access in contested electronic battle environments affected by jamming, interception, signal manipulation, and constantly changing operational conditions. I designed and architected use cases so that every element of workload, identity, and system could continue to operate independently and securely even in degraded or disrupted scenarios. In parallel, I defined the enterprise and solution security architecture with LeanIX, Bizzdesign, and HOPEX as enterprise architecture, repository, and governance platforms to maintain architecture inventory, relationships, traceability, target pictures, and security governance in complex environments. For the architectural designs, I used Sparx Enterprise Architect to describe formal architecture views, interfaces, trust boundaries, and system architecture in both IT and OT environments. IriusRisk was used for threat modeling of the solution to identify architecture-driven risks, derive security requirements, and detect countermeasures and design gaps directly from the solution models. Risk and compliance management was supported with Archer. Architecture decisions, control gaps, and operational risks were translated into controlled governance and auditable compliance measures. For documentation, collaboration, and visual design, I used Confluence to maintain Architecture Decision Records, Security Blueprints, and workflows. I used Lucidchart and draw.io to create design artifacts tailored to stakeholders. I also defined OT security concepts with support from electrical and mechanical engineers in the areas of oil, vehicle onboard systems, rail, power plants, pharma, gas turbines, and nuclear technology. I created the end-to-end OT security strategy, starting with global policy, developed into standards and procedures, and finally aligned with Bell-LaPadula, Purdue Model, SABSA, TOGAF ADM, CENELEC 50701, IEC 62443, and NIST standards. In addition, I worked with engineering team leads to identify critical KBP assets and place them under protective measures that segmented SCADA, PLC, and HMI assets. I drove collaboration between Security, IT, and OT teams to create standardized workflows and use cases for the OT security solution catalog, while integrating Defense-in-Depth and Zero-Trust principles into operational environments. A key part of my work was integrating multidisciplinary engineering, security, and operations stakeholders into a unified security blueprinting strategy and ensuring that architecture, threat modeling, governance, and documentation were technically strong and operationally practical.

• Plan & Prepare (Site Design & Readiness): Inventory & Design: Dell PowerEdge R-Series, Aruba Switches (L2/L3), Notebooks/Peripherals; Serial Numbers/Asset Tags, IPv4/IPv6 Addressing, VLAN/DHCP/DNS Plan

• Runbooks/MOPs: Site Rollout Runbook, Backout Strategy (<15–30 min), Risk Register, Communication Matrix; Approvals via CAB/Change

• Images/Packages: Golden Image (Win10/11), Driver Packs, BIOS/UEFI Baseline; O365/Teams/OneDrive-KFM; BitLocker Policies; MECM/SCCM, Intune/Autopilot, MDT/WinPE

• Logistics: Shipping/Customs Clearance, RMA/DOA, On-Site Spares; Tools (Barcode Scanners, Label Printers), "Go-Bag" (Cables, SFPs, Console Cables)

• Deliver (On-Site Implementation): Endpoints: Swap & Migration (USMT/OneDrive KFM), Peripherals (ATB/BT Printers, Scanners, Boarding Gate HW); Domain Join, Compliance Checks, O365 Activation, Printers/Queues, Network Drives

• Acceptance: Functional Tests for DCS/CUTE/CUPPS/CUSS Stations, Ticketing/Check-in Workflows, Boarding Gates

• Servers (R-Series): Rack & Stack, Cabling (PDU Redundancy, Fiber/Copper), Labeling/Nomenclature; Firmware/RAID (PERC), Lifecycle Controller, iDRAC Network; Windows Server 2022/2025 + CIS/BSI Hardening; Agents (Backup/AV/EDR/Monitoring), Time Service/NTP Auth, Syslog/SNMPv3

• Network (Aruba): VLANs, LACP Trunks, MSTP Root; Portfast + BPDU-Guard at Edge; QoS (EF/AF); Dual-Stack (v4/v6), DHCP Relay. NAC/802.1X with ClearPass/Radius/TACACS+, Roles + MAB Fallback; Guest Isolation, ACLs (Guest→Mgmt deny). Telemetry: sFlow, SNMPv3, Syslog→SIEM; LLDP→Inventory/CMDB

• Airport-Specific: CUTE/CUPPS/CUSS Terminals; DCS/Amadeus/SITA Connectivity; FIDS (read-only); Bag Tag/Boarding Pass Printing; Changes During Off-Peak/Night Windows

• Stabilize (Hypercare): First-Day Support, KPI Tracking (Login Times, Ticket Volume, Error Classes), QoS Fine-Tuning

• Troubleshooting: Wireshark/iperf, Event Logs, Switch Counters, sFlow Flows; Fast Incident Handling as SPOC

• Knowledge Transfer: Short Training Sessions for Station Teams, Mini-Runbooks (Incident/Recovery)

• Close (Documentation & Handover): Documentation & CMDB: Final Configs (Switch/Server), Topology/Patch Plans, IP Tables, Serial Number/Asset Lists, Before/After Photos

• Acceptance & Sign-off: UAT Protocols, Functional Evidence (Use Cases), Return/Reuse of Old Hardware

• Lessons Learned: Risks, Standard Packages, Driver Freeze, "Known Issues"

• Interfaces/Communication: Station IT, Airport IT, SOC/NOC, Ground Ops/Ramp/Check-in, Providers (SITA/Amadeus). ITSM: ServiceNow (Inc/Req/Change/KB), Handover to BAU

• Conducting cybersecurity readiness checks based on an in-house assessment methodology
• Analyzing the external attack surface using the Graydaxe EASM platform
• Assessing maturity levels and deriving prioritized recommendations for action

• Development of strategies, processes and system requirements to further develop the lead and campaign streams of a Salesforce system for the subsystems Sales Cloud, Marketing Cloud and Analytics Cloud
• Gathering and creation of marketing strategy concepts for direct sales, focusing on lead generation for new and existing customers
• Analysis and optimization of existing and new contact points
• Derivation of system requirements and user tests for new developments
• Establishment of a requirements and implementation process for business needs at the interface between CRM strategy and marketing system operations
• Facilitation of ideation workshops with the project's stakeholders
• Mediation between business and technical project stakeholders
• Analysis and post-documentation of existing marketing strategies and the system functions already created for them
• Analysis of target groups and pre-system data quality as a foundation for new CRM strategies
• Consultation on content and asset strategy for marketing campaigns
• Definition of KPIs and other performance criteria for the system and CRM strategy

• Configuration of Dell switches, routers, and access points.
• Troubleshooting and issue resolution.
• Extreme, Cisco and Dell switches and routers environment, Extreme A3 NAC, Extreme CloudIQ.