Linux, FreeBSD, NetBSD, OpenBSD, OS/X, Solaris. Windows XP/2k/2003/Vista/7. Virtualization - VMWare(Server &ESXi), XEN. Network/System Security Administration Penetration testing – Using mostly public open source resources. DISA STIGs, PCI DSS security standards. Intrusion Detection Systems - Snort, AIDE, OSSEC, Tripwire, Samhain, HostSentry, Portsentry, chkrootkit, rkhunter. Systems Hardening - SELinux, GRSecurity, Bastille. Troubleshooting. Creating technical solutions. Networking - TCP/IP, UDP, IPv4. Setting up firewalls, LANs, Wi-Fi, WLANs, VPNs, and secure data tunnels. BIND Administration (DNS & ReverseDNS). MySQL, PostgreSQL - Setup & Configuration. eMail systems - Exim, Sendmail, Postfix, Qpopper, Qmail, dovecot, AM