Network Security Information

"Insertion, Evasion, and Denial of Service: Eluding Network Intrusion Detection"
[Local PDF Version]
[Local HTML Version]
This paper highlights some of the problems with network-based intrusion detection and is quite good, if somewhat theorhetical. Written by T. Ptacek and T. Newsham of Secure Networks, now held in the clutches of Network Associates.
"Snort - Lightweight Intrusion Detection for Networks"
[Text Version]
[PostScript Version]
By Martin Roesch! ;-)  This paper discusses the architecture, performance, and uses of Snort. It also contains a comparative analysis of Snort to some other well know programs used for similar purposes.  Additionally, there is a nice rules tutorial contained in the document for those of you wanting to know how the rules system works.  I'll be presenting this paper at the USENIX LISA '99 conference next month in Seattle.
"CIFS: Common Insecurities Fail Scrutiny" Hobbit's great paper on why Windows networking can be hazardous to your (mental) health.
"Smashing the stack for fun and profit" From Phrack issue 49, Aleph1's excellent paper on buffer overflow concepts.
"Improving the security of your site by breaking into it" Dan Farmer and Wietse Venema's classic on why all hacking isn't necessarily bad hacking. A little dated, but still quite good.
"Techniques Adopted By 'System Crackers' When Attempting To Break Into Corporate or Sensitive Private Networks" This one is written more for the sysadmins out there so they can get a grasp of cracker tactics and worldview. By Network Security Solutions Ltd.