hanji's os links

Great tutorial on how to set up and configure multiple machines to watch a UPS and shutdown when the battery is low. Nut is a fantastic project with plenty of UPS driver support.

Tutorial on how to set up dual layer authentication with OpenVPN. Dual layer meaning standard TLS key based authentication couple with user/pass authentication using pam plugin

Fail2ban has been successfully used to protect SSH daemons, but this article talks about how you can use fail2ban to lessen the load of mailservers by blocking previously identified blacklisted IPs or relay access abuse. Howto is was written for Gentoo, but should easily be applied to any Linux distro.

Complete how to for upgrading mod_security-1.x to 2.x. Also discusses some of the issues related to that upgrade and offers migration matrix link to easily rework existing rules.

Simple how-to for installing and configuring policyd-weight policy daemon. Policyd-weight sits inline with Postfix and can reject mails before the data transaction. This is great for quickly IDing spammers and rejecting them before soaking up bandwidth and processing via spamassassin. How-to is geared towards Gentoo Linux, but can be easily applied to others.

Absolutely awesome how-to for creating a chrooted environment using mod_chroot. It's Gentoo specific (basically init scripts), but all distros should be able to use this. Very thorough!

How to configure grub to reboot into a fallback kernel after kernel panic.