Oleksandr T.

Senior System Administrator with 10+ years of hands-on experience supporting and building IT infrastructures for small and mid-size businesses. I help companies fix complex issues fast, stabilize their systems, strengthen security, and modernize their environments (Windows, Linux, Networks, M365, Firewalls). What I can do for you ✔ Office 365 / Microsoft 365 – migrations, tenant setup, mail flow, Exchange Online, SharePoint, OneDrive, Teams, hybrid AD ✔ Active Directory & Windows Server – GPO, user management, domain health, troubleshooting ✔ Linux (Ubuntu, Debian, CentOS) – server setup, hardening, automation, troubleshooting ✔ Firewalls & VPNs – Fortinet, pfSense, Mikrotik, WireGuard, OpenVPN, site-to-site & remote access ✔ Virtualization – VMware, Proxmox, Hyper-V ✔ Monitoring & Backups – Zabbix, Veeam, snapshots, disaster recovery planning ✔ Network setups – multi-site deployments, switches (Aruba, HP, Mikrotik), VLANs ✔ Infrastructure audits & optimization – performance, security, cost reduction Why clients hire me ✨ Fast problem-solving — I understand complex systems quickly and fix issues without wasting time ✨ Clear communication — I explain what’s happening and what will be done ✨ Reliable — I keep systems stable, secure, and documented ✨ Broad experience — Windows + Linux + networking + cloud + security ✨ Business-oriented — I help reduce downtime and optimize costs Typical projects I complete • Fix Office 365 mail flow issues • Set up secure VPN between branches • Clean up AD misuse, broken GPOs, DNS issues • Build a monitoring system with Zabbix • Secure and optimize existing infrastructure • Migrate servers or whole environments • Configure firewalls, VLANs, routing • Provide ongoing IT support / consulting If you need a technical expert who can quickly understand your environment and deliver stable, long-term solutions, let’s work together.