(http://www.tldp.org/HOWTO/Security-HOWTO/) (also available at LinuxSecurity? (http://www.linuxsecurity.com/docs/LDP/Security-HOWTO.html)) is one of the best references regarding general Linux Security. * The Security Quick-Start HOWTO for Linux (http://www.tldp.org/HOWTO/Security-Quickstart-HOWTO/) is also a very good starting point for novice users (both to Linux and security). * The Linux Security Administrator's Guide (http://seifried.org/lasg/) (provided in Debian through the `lasg' package) is a complete guide that touches all the issues related to security in Linux, from kernel security to VPNs?. Note that it has not been updated since 2001, but some information is still relevant. [1] * Kurt Seifried's Securing Linux Step by Step (http://seifried.org/security/os/linux/20020324-securing-linux-step-by-step.html). * In Securing and Optimizing Linux: RedHat? Edition (http://www.tldp.org/links/p_books.html#securing_linux) you can find a similar document to this manual but related to RedHat?, some of the issues are not distribution-specific and also apply to Debian. * IntersectAlliance? has published some documents that can be used as reference cards on how to harden linux servers (and their services), the documents are available at their site (http://www.intersectalliance.com/projects/index.html). * For network administrators, a good reference for building a secure network is the Securing your Domain HOWTO (http://www.linuxsecurity.com/docs/LDP/Securing-Domain-HOWTO/). * If you want to evaluate the programs you are going to use (or want to build up some new ones) you should read the Secure Programs HOWTO (http://www.tldp.org/HOWTO/Secure-Programs-HOWTO/) (master copy is available at http://www.dwheeler.com/secure-programs/, it includes slides and talks from the author, David Wheeler) * If you are considering installing Firewall capabilities, you should read the Firewall HOWTO (http://www.tldp.org/HOWTO/Firewall-HOWTO.html) and the IPCHAINS HOWTO (http://www.tldp.org/HOWTO/IPCHAINS-HOWTO.html) (for kernels previous to 2.4). * Finally, a good card to keep handy is the Linux Security ReferenceCard? (http://www.linuxsecurity.com/docs/QuickRefCard.pdf)