The Apache Foundation
Apache is the most widely used webserver software on the Internet and you can find a wealth of information about it here.
The Cathedral and the Bazaar by Eric S. Raymond
An anaysis of why open source development works.
Buy all kinds of Linux stuff!
Embracing Insanity: Open Source Software Development by Russell C. Pavlicek
Learn about Geek culture and the philosophy behind Open Source. A must read for techies, managers considering Open Source and anyone else who wants to explore the differences between closed source (proprietary) software and Open Source.
Google's Linux search page
GNU / Free Software Foundation homepage
Information about GNU software and the General Public License (GPL).
Good general information on iptables. I found the section on connection tracking particularly useful.
IP Tables State (iptstate)
Single-pass and top-like monitoring of iptables-based firewalls. Very handy!
Knoppix - bootable Linux on CD!
Useful as a demo, rescue CD or just "try it before you buy it" Linux. Way cool!
The Linux Documentation Project (TLDP)
A wealth of information about Linux including, FAQ's, Howto's, guides, program documentation, etc.
General information about Linux.
Online version of the printed magazine published by SSC.
Linux Online homepage
More general information about Linux.
Information & news about Linux. Maintained by Linux Journal.
Linux Weekly News
"Bringing you the latest news from the Linux world. Dedicated to keeping Linux users up-to-date, with concise news for all interests."
News and information about the Linux kernel.
Nmap - The Network mapper
"Audit your network security before the bad guys do." --nmap website
O'Reilly publishing (Animal & Nutshell series books)
Warning! These books may become addictive (and expensive). The first step is admitting you have a problem!
O'Reilly publishing's Safari Bookshelf
More than 2,000 books from over a dozen publishers available online. Search, preview or read cover to cover.
The Open Source homepage
Information about Open Source software.
The OpenSSH homepage
OpenSSH is a free, secure replacement for telnet, ftp and many of the Unix r* commands. Highly recommended for secure remote administration. Links to many OpenSSH clients and other SSH related resources on this site.
RedHat products plus Linux news & information
Replacing NT server with Linux
Migration from NetWare to NT, back to NetWare & finally to Linux. Includes a Linux vs. NT cost analysis of the Author's project.
Running Linux by Matt Welsh & Lar Kaufman
The print version is a little dated but good for general information.
Rusty's Remarkably Unreliable Guides
General information on Linux networking, firewalling & kernel hacking.
The Samba website. Samba provides file & print services for Windows, much like Novell Netware or Microsoft NT/2000.
Samba: Integrating UNIX and Windows by John D. Blair
Excellent book containing valuable information about configuring Samba. Includes CD-ROM.
Security related news & information for Linux and other operating systems.
Squid Internet object cache homepage
Good information to get started because Squid comes with limited documentation, most of which is in the configuration file.
The Tolis group
Home of "The BRU Guys". Makers of BRU (Backup and Recovery Utility) and other software.