Operating Systems: Windows Server, Linux (Red Hat, Ubuntu)
Networks: TCP/IP, LAN, WAN, VLAN, VPN
Virtualization: VMware, Hyper-V
Information Security: Firewalls (pfSense, Cisco ASA), Antivirus, IDS/IPS
Network Services: DNS, DHCP, LDAP, Active Directory
Monitoring Tools: Nagios, Zabbix, PRTG
Scripting Languages: PowerShell, Shell Script
Backup Tools: Veeam Backup & Replication, Bacula
Project Management: ITIL, Agile