A repetitive strain injury (RSI) is occupational overuse syndrome, non-specific arm pain or work related upper limb disorder. RSI caused from overusing the hands to perform a repetitive task, such as typing, writing, or clicking a mouse. Unfortunately, most people do not understand what RSI is or how dangerous it can be. You can easily prevent RSI using open source software called Workrave.
OpenSSH is the implementation of the SSH protocol. OpenSSH is recommended for remote login, making backups, remote file transfer via scp or sftp, and much more. SSH is perfect to keep confidentiality and integrity for data exchanged between two networks and systems. However, the main advantage is server authentication, through the use of public key cryptography. From time to time there are rumors about OpenSSH zero day exploit. This page shows how to secure your OpenSSH server running on a Linux or Unix-like system to improve sshd security.
From my mailbag:
How do I find out if a given PCI hardware is supported of by the current CentOS / Debian / RHEL / Fedora Linux kernel?
You can easily find out find out if a given piece of PCI hardware such as RAID, network, sound, graphics card is supported or not by the current Linux kernel using the following utilities under any Linux distributions.
The Blue Screen of Death (BSoD) is used for the error screen displayed by Microsoft Windows, after encountering a critical system. Linux / UNIX like operating system may get a kernel panic. It is just like BSoD. The BSoD and a kernel panic generated using a Machine Check Exception (MCE). MCE is nothing but feature of AMD / Intel 64 bit systems which is used to detect an unrecoverable hardware problem.
Program such mcelog decodes machine check events (hardware errors) on x86-64 machines running a 64-bit Linux kernel. It should be run regularly as a cron job on any x86-64 Linux system. This is useful for predicting server hardware failure before actual server crash.
Linux kernel is the central component of Linux operating systems. It is responsible for managing the system’s resources, the communication between hardware and software and security. Kernel play a critical role in supporting security at higher levels. Unfortunately, stock kernel is not secured out of box. There are some important Linux kernel patches to secure your box. They differ significantly in how they are administered and how they integrate into the system. They also allow for easy control of access between processes and objects, processes and other processes, and objects and other objects. The following pros and cons list is based upon my personal experience.
Geolocation software is used to get the geographic location of visitor using IP address. You can determine country, organization and guess visitors location. This is useful for:
a] Fraud detection.
b] Geo marketing and ad serving.
c] Target content.
d] Spam fighting.
e] And much more.
mod_geoip is a Lighttpd module for fast ip/location lookups. In this tutorial you will learn about mod_geoip installation and php server side examples to determine visitors country.
MAC Filtering (layer 2 address filtering) refers to a security access control methodology whereby the 48-bit address assigned to each network card is used to determine access to the network. Iptables, pf, and IPFW can block a certain MAC address on a network, just like an IP. One can deny or allow from MAC address like 00:1e:2a:47:42:8d using open source firewalls. MAC address filtering is often used to secure LAN or wireless network / devices. Is this technique effective?
The tail command is one of the best tool to view log files in a real time using tail -f /path/to/log.file syntax on a Unix-like systems. The program MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). This is one of those dream come true program for UNIX sys admin job. You can browse through several log files at once and do various operations like search for errors and more.
I’ve already written about creating a partition size larger than 2TB under Linux using GNU parted command with GPT. In this tutorial, I will provide instructions for booting to a flat 2TB or larger RAID array under Linux using the GRUB boot loader.