lpi2 book
http://web.archive.org/web/20011019150431/scn.snow.nl/lpi/
TCP IP
http://ns.kemsu.ru/Orelly/tcpip/index.html
http://wks.uts.ohio-state.edu/sysadm_course/html/sysadm-1.html
http://www.linux.cu/mirrors/www.oreilly.com/catalog/unix/lrnunix/index.htm
free bsd
http://www.freebsd.org/handbook/
web servers guide
http://www1.feralcat.net/webcd/
everyday linux
http://everydaylinux.com/