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