- Experience with Unix-like systems: FreeBSD, Linux distros; - Building and support high load server clusters with load balancing and failovering: nginx, haproxy; - Services failovering: DRBD, Pacemaker, some internal solutions; - Virtualization: Vmware ESXi/VCenter, KVM; - Experience in CISCO, CheckPoint, F5, KEMP devices; - VPN: IPSec, OpenVPN; - Software firewalls: pf, ipfw; - Installation, improvement and support of multiple unix services: nginx with php-fpm, apache, exim, postfix, dovecot, proftpd, named, mysql, postgresql, redis, dhcp, racoon, etc.; - System monitoring with nagios, cacti; - Centralized log collectors system: Splunk, syslog-ng; - Experience in configuration management system like cfengine; - Understanding and experience in computer networks, adjustment of unmanaged and managed L2/L3 switches, routers, firewalls, ADSL/SHDSL modems; - Installation, adjustment and support of OS Windows, applied software and services: DNS, NAT, VPN, ftp, mail, apache, firewall, etc.;