nixCraft Linux Sys Admin Blog

Linux / Windows Application For Prevention Of RSI (Repetitive Strain Injury)

Vivek Gite — 2009-11-04T11:21:00+01:00

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 serious it can be. You can easily prevent RSI using open source software called Workrave.

20 Linux Server Hardening Security Tips

Vivek Gite — 2009-10-30T12:52:11+01:00

Securing your Linux server is important to protect your data, intellectual property, and time, from the hands of crackers (hackers). The system administrator is responsible for security Linux box. In this first part of a Linux server security series, I will provide 20 hardening tips for default installation of Linux system.

Download Ubuntu 9.10 (Karmic koala) CD ISO Images

Vivek Gite — 2009-10-29T18:43:27+01:00

The latest version of the popular Linux desktop distribution Ubuntu 9.10 has been released and available from the official project web site. New features since Ubuntu 9.04 includes - Firefox 3.5, GNOME 2.28, an enforcing AppArmor profile, Linux kernel 2.6.31, ext4 file system (default), Empathy instant messenger instead of Pidgin, the Ubuntu One client, which interfaces with Canonical's new on-line storage system. It also includes a new application called the Ubuntu Software Center. A quick screen-shot tour of new features available here on our website.

BBC's Rory Cellan-Jones: Not Happy With Ubuntu Linux

Vivek Gite — 2009-10-27T23:17:03+01:00

BBC's blogger Rory Cellan-Jones took Ubuntu Karmic Koala for 24 hours test drive and predicated that - "... Ubuntu will remain a very niche product - but it's Google's Android which could bring open-source to the mass consumer market...".

Download of the day: OpenBSD 4.6 CD ISO Images

Vivek Gite — 2009-10-19T11:17:27+01:00

OpenBSD 4.6 has been released and available for download from the official website. OpenBSD is well known for record of more than ten years with only two remote holes in the default install. The OpenBSD is widely known for the quality open source code and documentation, uncompromising position on software licensing, and focus on security and code correctness.

Use a Linux LiveCD to Avoid Windows Malware For Netbanking

Vivek Gite — 2009-10-15T17:53:55+01:00

Internet has revolutionized the way online users can shop and avail banking services like internet Banking from anywhere, anytime without visiting bank. But, how safe is your money with online net-banking which allows to carry out money transfer? Companies and in some case individuals lost anywhere from $10,000 to $500,000 dollars because of a single malware infection. The cyber crooks are targeting innocent MS-Windows user. If you are concerned about how best to protect yourself from this type of fraud, use Linux LiveCD for online banking and avoid Microsoft Windows at all cost.

Celestia 3D Space Simulation Software For Linux / Windows / OS X

Vivek Gite — 2009-10-01T04:20:07+01:00

Celestia is a real-time visual space simulation astronomy program. It is a cross platform, open source software and released under the GNU General Public License. NASA and ESA have used Celestia in their educational and for interfacing to trajectory analysis software. It allows users to travel through an extensive universe, modeled after reality, at any speed, in any direction and at any time in history. Celestia displays and interacts with objects ranging in scale from artificial satellites to entire galaxies in three dimensions using OpenGL. It is a perfect software for astronomer, educator, student, and teacher for astronomy purpose.

The Upcoming Version of Linux Shell Scripting Tutorial v2.0

Vivek Gite — 2009-09-24T13:31:40+01:00

I've been working on the Linux Shell Scripting Tutorial v.2.0 for some time and now the updated version licensed under "Creative Commons Attribution Noncommercial Share Alike 3.0 Unported" of the same available in wiki format. It will contain a few significant changes from the previous versions of the tutorial, which includes a new topics, grammar & typo fixing and new sys admin related scripts.

How To: Upgrade Red Hat Enterprise Linux 5.3 to v5.4

Vivek Gite — 2009-09-02T23:22:59+01:00

Red Hat Enterprise Linux v5.4 has been released and available via RHN for immediate update. The new version includes the kernel-based virtual machine (KVM) virtualization, next generation of developer features and tools including GCC 4.4, a new malloc(). Also included clustered, high-availability filesystem to support Microsoft Windows storage needs on Red Hat Enterprise Linux.

Download Slackware 13.0 CD / ISO Images

Vivek Gite — 2009-08-30T17:28:43+01:00

Slackware version 13.0 has been released and available for download from the official project website. This release brings with it many major changes since Slackware 12.2, including a completely reworked collection of X packages (a configuration file for X is no longer needed in most cases), major upgrades to the desktop environments (KDE version 4.2.4 and Xfce version 4.6.1), a new .txz package format with much better compression, and other upgrades all around -- to the development system, network services, libraries, and major applications like Firefox and Thunderbird. Also, this is the first release of Slackware with native support for the 64-bit x86_64 architecture!

CentOS / Redhat Iptables Firewall Configuration Tutorial

Vivek Gite — 2009-11-10T09:59:13+01:00

How do I configure a host-based firewall called Netfilter (iptables) under CentOS / RHEL / Fedora / Redhat Enterprise Linux?

Answer to "CentOS / Redhat Iptables Firewall Configuration Tutorial"

Linux Configure Logwatch on the Central Log Server

Vivek Gite — 2009-11-10T09:00:37+01:00

I'm using Logwatch for reporting on unusual items in syslog. I've central logserver up and running. All other Linux servers send logs to a remote loghost called log.example.com. How do I configure Logwatch on the central log server so that it will send daily logs messages in a single e-mail?

Answer to "Linux Configure Logwatch on the Central Log Server"

Mac OS X Display Access Warnings Message For The Login Window

Vivek Gite — 2009-11-10T08:37:11+01:00

I know how to display notice of a computer's ownership, to warn against unauthorized access, under Linux gnome desktop. How do I display similar message under Apple Mac OS X to remind authorized users of their consent to monitoring?

Answer to "Mac OS X Display Access Warnings Message For The Login Window"

Linux Upgrade Password Hashing Algorithm to SHA-512

Vivek Gite — 2009-11-10T08:11:36+01:00

The default algorithm for storing password hashes in /etc/shadow is MD5. I was told to use SHA-512 hashing algorithm. How do I set password hashing using the SHA-256 and SHA-512 under CentOS or Redhat Enterprise Linux 5.4?

Answer to "Linux Upgrade Password Hashing Algorithm to SHA-512"

Linux Disable Mounting of Uncommon Filesystem

Vivek Gite — 2009-11-09T17:55:37+01:00

How do I disable mounting of uncommon file systems such as hfs, udf, cramfs etc under Fedora or CentOS / RHEL / Redhat Enterprise Linux?

Answer to "Linux Disable Mounting of Uncommon Filesystem"

Rsnapshot WARNING: Could not lchown() symlink "/path/to/file" Error and Solution

Vivek Gite — 2009-11-03T22:17:05+01:00

I got rsnapshot based backup server up and running for my network under Debian Linux 5.x. But, whenever I run a backup job using the following command:
rsnapshot -v -c /root/rsnapshot.server1.conf hourly
I get the following messages on screen:

WARNING: Could not lchown() symlink "/nas/.rsnapshot/hourly.1/server1.example.com/etc/alternatives/locate" WARNING: Could not lchown() symlink "/nas/.rsnapshot/hourly.1/server1.example.com/etc/alternatives/nc.1.gz" WARNING: Could not lchown() symlink "/nas/.rsnapshot/hourly.1/server1.example.com/etc/alternatives/jexec-binfmt" WARNING: Could not lchown() symlink "/nas/.rsnapshot/hourly.1/server1.example.com/etc/alternatives/servertool"

How do I fix this problem?

Answer to "Rsnapshot WARNING: Could not lchown() symlink "/path/to/file" Error and Solution"

Linux Convert an MP3 File to WAV Format

Vivek Gite — 2009-11-03T22:13:40+01:00

How do I convert an MP3 file to WAV format under Linux using a shell prompt?

Answer to "Linux Convert an MP3 File to WAV Format"

Linux Kernel /etc/sysctl.conf Security Hardening

Vivek Gite — 2009-10-27T21:55:00+01:00

How do I set advanced security options of the TCP/IP stack and virtual memory to improve security and performance of my system? How do I configure Linux kernel to prevent certain kinds of attacks using /etc/sysctl.conf? How do I set Linux kernel parameters?

Answer to "Linux Kernel /etc/sysctl.conf Security Hardening"

Linux Increasing The Transmit Queue Length (txqueuelen)

Vivek Gite — 2009-10-22T14:16:12+01:00

How do I set txqueuelen (the length of the transmit queue) length of the network card device under Linux? How do I set it for a high latency and/or a high speed network for bulk transfer from disturbing interactive traffic like ssh too much?

Answer to "Linux Increasing The Transmit Queue Length (txqueuelen)"

Linux MTU Change Size

Vivek Gite — 2009-10-22T13:55:39+01:00

We've gigabit networks, and large maximum transmission units (MTU) sizes (JumboFrames) can provide better network performance for our HPC environment. How do I change MTU size under Linux?

Answer to "Linux MTU Change Size"