// OS:
Debian / Ubuntu / SLES / Red Hat / CentOS / Slackware / Gentoo / FreeBSD / OpenBSD / IpCop / m0n0wall / pfSense / FreeNAS / Openfilter / Cisco Routers & Switches
// SERVICES:
FTP: Proftpd, Vsftpd, Pure-ftpd, Sftpd, Tftpd
FILE SHARING: Samba, NFS, NIS, WebDAV
PRINTING: Cups
CACHING ACCELERATORS: Varnish, Memcached, eAccelerator
WEB: Apache v1/2, Nginx, LightHTTPd, PHP v4/5
RUBY ON RAILS: Mongrel, Thin, Phusion passenger, Ebb, Unicorn, Capistrano, RVM
MAIL: Postfix, Dovecot, Courier, RBL, Postgrey, Spamassassin, Amavis, Razor, Pyzor, Clamav, Dcc, SPF
DATABASE: mysql v4/5 with Phpmyadmin, mysqlcluster, postgresql v7/8 with Phppgadmin, SQLite, redis
DNS: bind9, tinyDNS, powerDNS
PROXY: Haproxy, Pond, Squid with SquidGuard / DansGuardian / URLFilter
PACKET FILTERING: iptables, ipfwadm, netfilter
VERSIONING: SVN, CVS, GIT
IDS: Snort, Bastille, Chkrootkit, Rkhunter, Tiger, Tripwire, Aide
IPS: PortSentry, Fail2ban
MONITORING: Nagios, Cacti, Zabbix, Awstats, MRTG, Mon, Monit, Zenoss, Ntop, Munin, Htop, Vnstat, Bwm-Ng, Iptraf, Nmap, Darkstat
VPN: PPTP, OpenVPN, IPsec
KERNEL: Kernel v2.4/2.6 - updates / patches (Openwall / Grsecurity / other), SELinux, LSM, AppArmor, RSBAC, FBAC-LSM
ROUTING/SWITCHING/WAN: Static Routing, Rip v1/2, (E)IGRP, OSPF(V3), VLANS, VTP, STP, Inter VLAN Routing, PPP, FR, Network Security, ACLs, IP Addressing, NAT
VPS: OpneVZ, XEN, KVM, Linux-VServer
BACKUP/RECOVERY: Mondo Rescue, PartImage, Clonezilla, Rsync, Rsnapshot, Tar, Dump / Restore, Duplicity, Bacula, Backup-Manager