Linux Proves – The Best Things In Life Are Free

Posted on in Categories Linux, Linux desktop, RedHat/Fedora Linux last updated March 16, 2009

They say – there’s no such thing as a free lunch. But, Linux and FOSS software can be used to start, run and grow your business for, you guessed it, free. February survey of IT managers by IDC indicated that hard times are accelerating the adoption of Linux. The open source operating system will emerge from the recession in a stronger data center position than before, concluded an IDC white paper.

Missing Memory

Posted on in Categories Howto, Linux, RedHat/Fedora Linux, Sys admin, Troubleshooting, UNIX, Windows server last updated March 13, 2009

Today, I’ve upgraded total 8 servers from 4GiB to 8GiB to improve performance of system by inserting additional memory modules. We started each server and checked for memory count at console. All severs booted normally after the upgrade and services such as SMTP, NFS, CIFS, HTTP started as expected. Shortly, afterwords I got a call from help desk about pop3 server for slow performance.

Tips To Protect Linux Servers Physical Console Access

Posted on in Categories Debian Linux, Hardware, Howto, Kde, Linux, Linux desktop, Linux distribution, package management, RedHat/Fedora Linux, Sys admin, Tips, Ubuntu Linux last updated March 12, 2009

This is an user contributed article.

Linux computer console is a physical device to operate a computer / server. Here are few steps which, if taken, make it more difficult for an attacker to quickly modify a system from its console.

Dealing with Recession – Saving Money With Free and Open Source Software

Posted on in Categories Debian Linux, Howto, Linux, Linux desktop, News, RedHat/Fedora Linux, Ubuntu Linux last updated March 2, 2009

According to wikipedia – “An economy which grows over a period of time tends to slow down the growth as a part of the normal economic cycle. An economy typically expands for 6-10 years and tends to go into a recession for about six months to 2 years”. The current defaults on homeloan have led to a major crisis in the US. Once recession started consumers lose confidence in the growth of the economy and spend less including technology and software. Is free and open source software (FOSS) a way to cut business costs? As concern about recession – even depression – deepens, more and more companies are asking this question. However, many have trouble knowing how to begin to find an answer.

Security Through Obscurity: MAC Address Filtering ( Layer 2 Filtering )

Posted on in Categories data center, fedora linux, FreeBSD, Gentoo Linux, GNU/Open source, Hardware, Iptables, Linux, Networking, RedHat/Fedora Linux, Security, Ubuntu Linux, UNIX, Windows, windows vista, Wireless networking last updated February 17, 2009

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?

Debunking the "Linux is virus free" Myth

Posted on in Categories Debian Linux, Howto, Linux, Linux desktop, RedHat/Fedora Linux, Security, Shell scripting, Ubuntu Linux, Windows, windows vista last updated February 11, 2009

Is Linux is virus free? The author of foobar blog provides some insight about the same. Linux users can’t just catch a virus by email or downloading malware from the Internet, contrary to “those Windows users”. From the foobar blog post:

Then you save an email attachment under Linux, the execute flag is normally NOT set and thus, the file can’t be executed just by clicking on it. So, no luck?

How To Tail (View) Multiple Files on UNIX / Linux Console

Posted on in Categories data center, Debian Linux, Download of the day, fedora linux, File system, FreeBSD, Gentoo Linux, GNU/Open source, Howto, Linux, Linux Log Management, Monitoring, package management, RedHat/Fedora Linux, Suse Linux, Sys admin, Tip of the day, UNIX last updated February 9, 2009

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.

Linux Convert ext3 to ext4 File system

Posted on in Categories CentOS, Data recovery, Linux, Linux desktop, Linux distribution, RedHat/Fedora Linux, Storage, Suse Linux, Sys admin, Tips, Troubleshooting, Tuning, Ubuntu Linux last updated January 23, 2009

Some time ago ext4 was released and available for Linux kernel. ext4 provides some additional benefits and perforce over ext3 file system. You can easily convert ext3 to ext4 file system. The next release of Fedora, 11, will default to the ext4 file system unless serious regressions are seen. In this quick tutorial you will learn about converting ext3 to ext4 file system.

Vsftpd FTP Server With Virtual Users ( Berkeley DB + PAM )

Posted on in Categories CentOS, FTP Server, Howto, Linux, Networking, package management, RedHat/Fedora Linux, Security last updated January 21, 2009

VSFTPD supports virtual users with PAM (pluggable authentication modules). A virtual user is a user login which does not exist as a real login on the system in /etc/passwd and /etc/shadow file. Virtual users can therefore be more secure than real users, because a compromised account can only use the FTP server but cannot login to system to use other services such as ssh or smtp.

Vsftpd Set Download Only Anonymous Internet Server

Posted on in Categories CentOS, fedora linux, Howto, Iptables, Linux, Networking, PF Firewall, RedHat/Fedora Linux, Security last updated January 21, 2009

This example shows how you might set up a large internet facing FTP site for distributing file or software updates. The emphasis will be on security and performance. VSFTPD will make sure only world-readable files and directories are served to the world via anonymous / ftp account. You force to originates FTP port connections from a secure port – so users on the FTP server cannot try and fake file content. You will hide the FTP server user IDs and just display ftp in directory listings. This is also a performance boost. Set a 40000-60000 port range for passive connections. This will help firewall setup.