Linux Articles

SARG – Squid Analysis Report Generator Configuration is a tool that allow you to view “where” your users are going to on the Internet. SARG provides many information about Squid users activities like, times, bytes, sites, etc… Download latest version of SARG from here. # wget http://...

If you run a dual-boot system with Linux and Windows, and reinstalling Windows XP after OS corrupt.  Windows XP will wipes over write grub entry or writing MBR sector. To recover GRUB, STEP 1: Boot off the Live CD enter into rescue mode, STEP 2: Open a Terminal and type in the following commands, noting that the first command will put you into the grub “prompt”, and ...

You can easily block SSH server attacks including dictionary based attacks and brute force attacks using a Python based script - DenyHosts. It analyzes the sshd log messages to determine what hosts or IPs are attempting to hack into your system. STEP 1: Enable Rpmforge Repo in your system, For 32bit CentOS / RHEL Linux enter: # rpm -Uhv...

For mysql, the system administrator user is called root. We will use the mysqladmin utility from a command line to set the new password. Default password is not secured at all. By default in RedHat, Fedora and Centos default password is null. So it is always better to set root password. To re-set root password, first stop mysql service. # service mysqld stop # mysqld_safe...

By default, when we are creating new user to Linux OS, all files from /etc/skel are copied to the new user's home directory. There are few files included in /etc/skel/ by default. * /etc/skel/.bash_logout * /etc/skel/.bashrc * /etc/skel/.profile * /etc/skel/.cshrc If you want to share some files, including rules and regulations to new users, simply add it...

PowerDNS is a DNS server, written in C++ and licensed under the GPL. It runs on most Unix derivatives and on Microsoft Windows. PowerDNS can be managed through a web interface (PowerAdmin). Install MySQL, # yum install mysql* -y After installation, start it and create system startup links for MySQL. # service mysqld start; chkconfig mysqld on If you want to set root password, # mysqladmin -u root...

YUM is an interactive, rpm based, package manager. It can automatically perform system updates, including dependency analysis and obsolete processing based on "repository" metadata. It can also perform installation of new packages, removal of old packages and perform queries on the installed and/or available packages among many other commands/services (see below). yum is similar to other high level package ...

MAC stands for Media Access Control and in a sense the MAC address is a computer's true name on a LAN. An Ethernet MAC address is a six byte number, usually expressed as a twelve digit hexadecimal number. To change this setting, we’ll need to edit the /etc/network/interfaces file. You can choose to use a different editor if you’d like. $ sudo gedit /etc/network/interfaces You s...

Istanbul is a desktop session recorder for the Free Desktop. It records your session into an Ogg Theora video file. To start the recording, you click on its icon in the notification area. To stop you click its icon again. It works on GNOME, KDE, XFCE and others. It named Istanbul because, Istanbul as a tribute to Liverpool's 5th European Cup triumph in Istanbul on May 25th 2005. To install Istanbul, # yum...

By default, MySQL only allows connections from the localhost address – 127.0.0.1. The configuration file is usually found in /etc/my.cnf. To switch MySQL to listen on TCP, Open /etc/my.cnf or /etc/mysql/my.cnf. # vim /etc/my.cnf Modify line as below # bind-address  = 127.0.0.1 Save and Exit the file. Now restart the database server by executing, # /e...

“ViCompress HTTP proxy server reduces download time by gzip compressing text pages before sending them on the client. This results in faster download times, especially over slow network connections. ViCompress works with existing web servers and web browsers. All modern browsers (Internet Explorer, Firefox, Safari, Chrome) recognize gzip-encoded data, and will automatically decompress the data on the f...

An ISO image is an disk image of an optical disc using a conventional ISO format. ISO image files typically have a file extension of .ISO. The name "ISO" is taken from the ISO 9660 file system used with CD-ROM media, but an ISO image can also contain UDF file system because UDF is backward-compatible to ISO 9660. You can mount an ISO images via the loop device under Linux. To mount ISO...

There are a number of different ways to do root password recovery on a Linux system. Different distributions make it easier than others. You must be physically in front of the system. For Red Hat and Mandrake: Boot from your first install CD and as the very first screen comes up hit F2 and type: rescue ( For RedHat "linux rescue" ) and the computer will boot in rescue mode....

The Multi Router Traffic Grapher (MRTG) is a network or resource monitoring tool used by System Administrators across the Globe. MRTG generates HTML pages containing PNG images, which provides a real time visual representation of network traffic and system resources. STEP 1: Install MRTG with required packages # yum install mrtg net-snmp net-snmp-utils -y STEP 2:...

“MemCached” is a high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.  Activate the RPMForge repository, #wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.i386.rpm # rpm -ivh rpmforge-release-0.5.2-2.el5.rf.i386.rpm Now install memcache rpm from rpm...

For mysql, the system administrator user is called root. We will use the mysqladmin utility from a command line to set the new password. Default password is not secured at all. By default in RedHat, Fedora and Centos default password is null. So it is always better to set root password. To set root password, # mysqladmin -u root password XyZ@aBc@123 # mysqladmin -u root -h ...

In computer science, Memory Leakage occurs when a computer software or program consumes required memory but unable to memory after completing its task or when no longer needed to Operating System. There are two types of Memory Leakage. One is Virtual Memory Leakage and another is Real Memory Leakage. Now first Identify cached memory or unused memory by executing, ...

Wireshark Network Analyzer is use full to track network packets. To sniff MySQL packets and decoding it, we will use mysqlsniffer. Note: This will not usually work for local connections. First, install libpcap-dev, which is the development library that allows an application to sniff network packets. $ sudo  apt-get install ...

Every time I connect to Linux server, I receive the same message and I’m getting tired of seeing it, so I decided to change the message to something else. Here’s the message that I get every time: [root@server1 ~]# ssh linuxarticles.org root@linuxarticles.org's password: Last login: Mon Oct 11 18:58:43 2010 from loc...

There are various methods to run multiple instances of mysql (on different ports) on the same machine. Here I have used the same binary and used a separate configuration file (with separate port, pid, socket and data directory). We need to create new directories for our datadir and log folder (if used). Also we need to assign proper permissions on those folders: # mkdir /var/lib/mysql2 # chown -R mysql.mysql...

memtester is a user-space utility for testing the memory subsystem in a computer to determine if it is faulty. It does a good job of finding intermittent faults and non-deterministic faults. It has many tests to help catch borderline memory. memtester should compile and run on any 32- or 64-bit Unix or Unix-like system. Download latest version of memtester from...

In Linux you can use faillog command to display failed login attempts or you can set login failure limits. faillog formats the contents of the failure log from /var/log/faillog database / secure log file. It also can be used for maintains failure counters and limits. For RHEL/CentOS Linux 5.x, you need to modify /etc/pam.d/system-auth file to monitor or track failed login attempts. You need to...

Nginx quickly delivers static content with efficient use of system resources. It can deploy dynamic HTTP content on a network using FastCGI handlers for scripts, and can serve as a very capable software load balancer. Nginx uses an asynchronous event-driven approach to handling requests which provides more predictable performance under load, in contrast to the Apache HTTP server model that uses a threaded or...

vmstat reports  information about processes, memory, paging, block IO, traps, and cpu activity. The first report produced gives averages since the last reboot.   Additional  reports  give information on a sampling period of length delay. The process and memory reports are instantaneous in either case. [root@linuxArticles.org ~]# vmstat -s 4087800  total memory 1643176  used m...

Linux kernel has PC speaker bell driver called pcspkr.ko. It is responsible for generating beeps while users are working on Shell Prompts ( Both Virtual and GUI Terminals ). If you don't like it, simply remove driver from kernel. Login as a root and type the following command to unload the driver: # rmmod -v pcspkr Sample output: rmmod pcspkr, wait=no We...