// IT & Cybersecurity Specialist

Efekan Yıldırım
Dabanıbüyük

↳ dabanibuyuk.com

I keep corporate IT infrastructure secure, efficient, and running without interruption — and I don't stop at keeping it alive, I make it better. Networks, firewalls, virtualization, and cloud.

system.status
roleIT & Cybersecurity Specialist
locationİstanbul / Türkiye
focusNetwork · Security · Cloud
3+
years experience
30+
companies supported
17
certifications
6
languages
// about

Infrastructure that stays secure and keeps improving

As an IT Specialist focused on infrastructure management and system operations, I make sure corporate IT processes run securely, efficiently, and without interruption. I work hands-on across network infrastructure, virtualization environments, Microsoft 365 administration, Active Directory, firewall configuration, and backup systems.

I actively deploy, manage, and optimize modern technologies such as M365, VLAN, next-gen firewalls, SD-WAN, NAC, SIEM, MFA, and cloud-based solutions. On the hardware side, I handle the full lifecycle of on-premise infrastructure — from HPE server installation and administration to Synology NAS deployment, configuration, and ongoing management. My approach isn't just to keep systems running — it's to continuously make them more efficient, secure, and sustainable.

// experience

Work

Aug 2025 — Present
IT Specialist
Técnicas Reunidas
İstanbul, Türkiye · Hybrid
  • Manage and optimize critical IT operations across multiple project offices — Istanbul Head Office, Rönesans Ceyhan PDH-PP, and TÜPRAŞ İzmit Refinery — aligned with global corporate standards.
  • Support the SOCAR HAOR Project in Azerbaijan, delivering cross-regional infrastructure, network, and systems administration under global cybersecurity policies.
  • Administer Cisco networking, FortiGate security, HPE & Synology servers, Microsoft Intune endpoint management, and SharePoint Online.
  • Hands-on FortiGate configuration — policies, NAT, VPN tunnels, security profiles — plus SD-WAN, VLAN segmentation, inter-VLAN routing, and Azure AD (Entra ID) identity & access.
FortiGateCiscoAzure ADIntuneSD-WAN
May 2023 — Jul 2025
Negmar Shipping Investment Inc.
İstanbul, Türkiye · On-site
Group IT Specialist
  • Oversaw IT operations across 30+ companies within the Negmar Group, aligning infrastructure with organizational goals.
  • Led IT planning, vendor coordination, and cross-departmental collaboration for infrastructure, security, and cloud strategy.
  • Built the foundational infrastructure for a newly launched investment bank — secure data-center connectivity, domain/DNS configuration, and core provisioning.
  • Drove high-level decisions on cybersecurity, business continuity, and technology investments as a bridge between technical teams and leadership.
InfrastructureCloud StrategyFirewallsBusiness Continuity
Group Assistant IT Specialist
  • Delivered IT support across ~30 companies spanning maritime, finance, software, gaming, mining, manufacturing, food, construction, and leasing.
  • Managed VMware virtualization, Dell PowerStore 500 & QNAP storage, Active Directory, Microsoft 365, and IIS.
  • Administered FortiGate/Sophos firewalls, Bitdefender AV, Veeam backups, and Aruba/Huawei/Ruijie/UniFi switching & Wi-Fi.
  • Ran monitoring (Zabbix, PRTG), CCTV (Hikvision, Dahua), ITSM (ManageEngine), DLP (Symantec), IP PBX (Grandstream), and ERP systems.
VMwareVeeamActive DirectoryMicrosoft 365Zabbix
// stack

Technologies

Network & Security

FortiGateSophosCiscoNG FirewallSD-WANVLANNACVPNIPSecNAT

Cloud & Identity

Microsoft 365Azure AD / Entra IDIntuneSharePointAWSMFA

Virtualization & Storage

VMwareESXiDell PowerStoreSynologyQNAPHPE

Systems & Backup

Active DirectoryWindows ServerIISVeeamZabbixPRTG

Security Operations

SIEMThreat HuntingDLP · SymantecBitdefenderEthical Hacking

Infrastructure & Ops

ArubaHuaweiUniFiHikvision CCTVDahuaGrandstream PBXManageEngine
// certifications

Licenses & certifications

// education

Education

Jun 2026 — Present
Master's, Computer Engineering (Thesis)
İstanbul Nişantaşı University
2023 — 2026
Bachelor's, Management Information Systems
Anadolu University
2021 — 2023
Associate's, Computer Programming
İstanbul Nişantaşı University
// articles

Writing

Notes and how-tos from the field — FortiGate, networking, and cloud security. First pieces coming soon.

Network Security

Configuring Site-to-Site IPsec VPN on FortiGate

A step-by-step walkthrough of phase 1/2 setup, routing, and firewall policies for a stable tunnel between two sites.

Coming soon
Networking

VLAN Segmentation & Inter-VLAN Routing, Explained

Why segmentation matters for security, and how to route between VLANs cleanly without opening the whole network.

Coming soon
Cloud Security

Hardening Microsoft 365 with MFA & Conditional Access

Practical baseline policies to protect identities in M365 / Entra ID without breaking day-to-day work.

Coming soon
// contact

Let's talk

Questions or just to connect — here's the fastest way to reach me:

info@dabanibuyuk.com
phone +90 535 599 41 13 location İstanbul / Türkiye