Monitor your system and network in real time...
http://www.cyberciti.biz/tips/top-linux ... tools.html
Free Server and Network Monitoring tools..
http://sixrevisions.com/tools/10-free-s ... -kick-ass/
http://www.slac.stanford.edu/xorg/nmtf/nmtf-tools.html
http://www.tecmint.com/command-line-too ... rformance/
Bandwidth Monitoring tools..
http://www.dynacont.net/documentation/l ... onitoring/
Advanced Bash scripts and commands..
http://www.commandlinefu.com/commands/browse
Teach yourself iptables..
http://www.thegeekstuff.com/2011/01/ipt ... damentals/
Everything about iptables(for intermediate and advanced users)..
https://help.ubuntu.com/community/IptablesHowTo
http://www.frozentux.net/iptables-tutor ... orial.html
http://ubuntuforums.org/showthread.php?t=668148
http://www.cyberciti.biz/faq/linux-web- ... -tutorial/
Iptables quick reference(apply the rules immediately!)..
http://www.thegeekstuff.com/2011/06/ipt ... -examples/
Become a system administrator..
http://www.thegeekstuff.com/2010/12/50- ... tutorials/
Build your own apache2 webserver..
http://library.linode.com/web-servers/a ... e-pangolin
Web server building/securing/clustering ..etc.. Knowledge-base..
https://help.ubuntu.com/community/Servers
Linux Advanced Routing & Traffic Control HOWTO..
http://dennishenry.net/docs_files/linux/routing.html
The Linux System Administrator's Guide
http://dennishenry.net/docs_files/linux/sysadmin.html
Move around the command line expertly..
http://dennishenry.net/docs_files/linux/tools.html
Learn to use tar/grep/find/awk/sed/diff/vim/sort..etc..
http://www.thegeekstuff.com/2010/11/50-linux-commands/
Become a CSS(cascading style sheet) maestro...
http://www.w3schools.com/css/css_examples.asp
https://calomel.org/