Installation and administration unix/linux servers for different tasks, like hosting, email server, dns server, domain controller, storage, backup server e.t.c. Installation and administration of networks and network environment: routers (cisco, mikrotik), switches (cisco, hp, zyxel), wi-fi routers and access points. Installation and administration asterisk pbx, voice gates (grandstream, eltex), ip telephones(cisco, linksys, yealink). Installation and administration different services. Technical support and troubleshooting problems.