Linux :
Databases : Mysql , Postgresql , Sybase
Web : Nginx, Apache 1/2, Tomcat, Glassfish , PHP, html
Management : Ansible, Cfengine
Monitoring : nagios, icinga, grafana, logstash, elasticsearch
Voip : Voicemaster , asterisk , ser, PortaBilling, Yate
Mail : Sendmail , Postmaster , qpopper , QMAIL , vpopmail, Courier IMAP, Cyrus IMAP , Mailscanner (
Antivirus + Antispam ), spamassasin, clamav,
fprot + squid proxy
Various linux distributions ( Ubuntu, SuSE, Gentoo, Debian, RedHat, Centos)
Firewalls (Iptables )
Routing - BGP, iproute2 (tc + ip), cisco ios
scripting - perl, bash , PHP, python
Virtualization - KVM, Hyper-V, Vmware ESXi , Virtuozzo, Openvz
Control Panels : Cpanel, Plesk, Ensim
Streaming/Transcoding : ffmpeg, RTMP
Windows:
Windows 2003, 2008 and 2012 Server Administration
Databases - MS SQL administration
Web - IIS, Tomcat, Glassfish
Mail - Hmail, Smartermail
scripting - Powershell
Virtualization - Microsoft Hyper-V , Virtuozzo
Control Panel : Plesk, Websitepanel