Mailing Lists

If you aren't on this list, get on it. Almost every exploit hits this list before they end up all over the news. It is full-disclosure, so exploits are usually posted here and can be tested on your systems/hardware. High traffic though.

Weekly (mostly) summary of discussions on the Linux-kernel mailing list.

For the poor souls forced to admin NT systems.

News

Good Linux news site updated weekly.

This page used to house website defacements. It is now mostly articles and stuff.

Programming

Just what it says.

Great online Oreilly book.

An online PERL cookbook.

Reviews

Good hardware/software review site tailored for UNIX users.

Security

Excellent monthly security newsletter.

An interesting list of default passwords for many systems listed here. Be careful not to leave default passwords on any devices/systems.

SANS site keeping track of day-to-day attacks.

Keeps a database of misconfigured networks that allow ICMP broadcasts.

Collection of public proxy servers.

Good document on secure programming.

Houses all of the Bugtraq-reported vulnerabilites. Good for searching for vulnerabilites in software/systems. Too many damn banners/frames though.

System Administration

Very good collection of documents on the Linux kernel.

Very good reference on Solaris TCP/IP tuning and ndd.

The definitive Solaris FAQ.