Windows Server (2003/20082012): AD, DFS, WDS, Windows Server Cluster, WSUS, DNS, DHCP. Linux(Debian/Ubuntu), FreeBSD: HAProxy, Nginx/Apache, Samba, firewall, DNS, DHCP, FTP. OpenStack, ElasticSearch. Visualization: KVM, LxC, VMWare(ESXi). DBMS support: MS SQL, Sybase ASE. Monitoring: Nagios, ELK, Graphite/Grafana, Zabbix. Automation: Ansible. Cisco networking hardware, Juniper switches, Dell and HP servers, storage (HP MSA, EVA SAN), Avaya telephony, Polycom videoconferencing, IPC Alliance MX.