General
- “20 Linux Server Hardening Security Tips” at UnixCraft – http://www.cyberciti.biz/tips/linux-security.html
- “Linux Security Basics” by Michael Dougherty (2010.07.05) – http://www.brighthub.com/computing/linux/articles/76572.aspx
Passwords
- “Info: Enforcing a Strict Password Rule” by “kopeah” (OverClock.net; 2005.07.11) – http://www.overclock.net/faqs/33217-info-enforcing-strict-password-rule.html
- “7 Examples to Manage Linux Password Expiration and Aging Using chage” by Dhineshkumar Manikannan (2009.04.23) – http://www.thegeekstuff.com/2009/04/chage-linux-password-expiration-and-aging/
Logging and auditing
- “Quick HOWTO : Ch17 : Secure Remote Logins and File Copying” (LHN) – http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch17_:_Secure_Remote_Logins_and_File_Copying
Related:
- SSH, OpenSSH – https://eikonal.wordpress.com/2010/12/16/ssh-openssh/
Eikonal Blog 
