Профессионально - Unix/Linux, VoIP, etc.

Platforms: Linux (Gentoo, Debian, CentOS, Fedora Core, Red

Hat, Ubuntu), UNIX (FreeBSD, Solaris), CiscoIOS, Cisco,

Linksys, D-Link, 3com.

Languages: C/C++, Perl, Shell, SQL, HTML.

Databases: PostgreSQL, MySQL, etc.

Firewalls: iptables, pf, ipfw, etc.

WEB-servers: Apache(1/2), Nginx, Lighttpd, etc.

FTP-servers: ProFTPd, vsFTPd, etc.

Mail-servers: Sendmail, Exim, Postfix, Cyrus, Dovecot, etc.

DNS-server: Bind.

VPN: OpenVPN, IPSec, PPTP, L2Tp, Vtund, etc.

Proxy: Squid, socks5.

Security: Syslog, Snort, etc.

Monitoring: Nagios, Cacti.

Version Control: CVS, SVN, Git, Perforce etc.

Bug Tracking: Bugzilla.

Backup: Amanda.

VoIP: Asterisk/Callweaver/FreePBX, SIP, H.323, IAX, PRI (Call centers/Office PBX).

Other: Anti-DDOS, Anti-SPAM sollutions.