Thursday, October 25, 2012

Install Windows 7 from USB drive using DISKPART

Windows 7 can be installed from a USB drive when the other installation methods are unavailable. We can choose between a memory card, hard drive which is USB compatible etc., and also several 3rd party tools are available for creating a USB bootable Windows 7 installation media, but I am using the...

Thursday, October 18, 2012

Linux Hotplug a CPU

How do I hotplug a CPU on a running Linux system? I would like to dynamically enable or disable a CPU on a running system? Linux kernel does supports cpu-hotplug mechanism. You can enable or disable CPU without a system reboot....

Content Filter by Using Squid, Squid guard / Dansguardian at Free-of-Cost

INTRODUCTION             The post fully deals with several parts of internet based utilities and restrictions that are mainly used in IT industry like to limit the web access for some users to a list of accepted/well known web servers and/or URLs...

Monday, October 15, 2012

Create test file using fsutil Windows

The “fsutil” in windows is much similar to the “dd” tool in linux, as both of them can be used to create test files of any size. How to: Execute the fsutil command in the elevated command prompt. (Command Prompt > Run as Administrator) fsutil file createnew filename file-size-in-bytes For...

Tuesday, October 9, 2012

HTTP Error 500.21 - Internal Server Error Handler "PageHandlerFactory-Integrated" has a bad module "ManagedPipelineHandler" in its module list

I just deployed a brand new .Net 4 website in IIS on my machine and get this error: ...

Wednesday, October 3, 2012

Controlling Web Access With SQUID

This summary is not available. Please click here to view the pos...

The Linux Boot Process in Detail

1. When a PC is booted it starts running a BIOS program which is a memory resident program on an EEPROM integrated circuit. BIOS – Basic Input Output of the System EEPROM - Electrically Erasable Programmable Read-Only Memory ...

Thursday, September 27, 2012

Sudo Full Practical Session

Introduction Before we proceed, it would be best to cover some basic user administration topics that will be very useful in later chapters. Adding Users One of the most important activities in administering a Linux box is the addition of users. Here you'll find some simple examples to provide a...

Wednesday, September 26, 2012

Using chkconfig to Start Daemons at Each runlevel

As stated earlier, the chkconfig command can be used to adjust which applications start at each runlevel. You can use this command with the --list switch to get a full listing of packages listed in /etc/init.d and the runlevels at which they will be on or off: ...

Basic's of Networking

1. Define Network? A network is a set of devices connected by physical media links. A network is recursively is a connection of two or more nodes by a physical link or two or more networks connected by one or more nodes. 2. What is a Link? At the lowest level, a network can consist of two or more...

Friday, September 21, 2012

Linux / Unix Commands For Connecting To The Serial Console

Most embedded Linux / BSD systems such as routers, servers and nas devices comes with console interface (serial port with RS-232). BIOS can use this, and after boot BIOS screen I/O is redirected so that you can use the device. RS-232 is also used for communicating to headless server, where no monitor or keyboard is installed, during boot when operating system is not running yet and therefore no network connection is possible. You need...

How To Check and Use Serial Ports Under Linux

How do I check and configure serial ports under Linux for various purposes such as modem, connecting null modems or connect a dumb terminal? Linux offers various tools. Linux uses ttySx for a serial port device name. For example, COM1 (DOS/Windows name) is ttyS0, COM2 is ttyS1 and so on. Task: Display Detected System's Serial Support Simple run dmesg command ...

Tuesday, September 18, 2012

Troubleshooting Disk and Data store Related Issues  SHOOT:2

SHOOT: 2 VMFS Lock Volume is Corrupted Details You may observe the following events within the /var/log/vmkernel logs within your VMware ESX host: Volume 4976b16c-bd394790-6fd8-00215aaf0626 (san-lun-100) may be damaged on disk. Corrupt lock detected at offset 0 Note: In this example 4976b16c-bd394790-6fd8-00215aaf0626 represents the UUID of the VMFS datastore and san-lun-100 represents the name of the VMFS datastore. You may...

Troubleshooting Disk and Data store Related Issues  SHOOT:1

SHOOT: 1 Troubleshooting a VMFS resource volume that is corrupted The event indicates the reported VMFS volume is corrupted. Example If 4976b16c-bd394790-6fd8-00215aaf0626 represents the UUID and san-lun-100 represents the associated volume label, you see: For Event: vmfs.lock.corruptondisk ...

Wednesday, September 12, 2012

Allow A Normal User To Run Commands As root Under Linux / UNIX Operating Systems

From my mail bag: I would like to run few commands such as stop or start web server as a root user. How do I allow a normal user to run these commands as root? You need to use the sudo command which is use to execute a command as another user. It allows a permitted user to execute a command as the superuser or another user, as specified in the /etc/sudoers (config file that defines or list of who can run what) file. The sudo command...

Wednesday, September 5, 2012

Shell Script To Encrypt Any Given Text File

In cryptography, encryption is the process of transforming information (referred to as plaintext) using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. Mcrypt is a simple crypting program, a replacement for the old unix crypt. When encrypting or decrypting a file, a new file is created with the extension .nc and mode 0600. The new file keeps the modification...

Shell Script List All Top IP Address Accessing Apache Web Server

******************************** #!/bin/bash # Shell Script To List All Top Hitting IP Address to your webserver. # This may be useful to catch spammers and scrappers. # where to store final report? DEST=/var/www/reports/ips ...

Basic of Shell Script

What Is a Shell? Ø       The shell is a user program or it is an environment provided for user interaction. Ø       It is a command language interpreter that executes commands read from the standard input device such as keyboard or from a file. Ø       The shell gets started when you log in or open a console (terminal). Ø      ...

Linux log files location and how do I view logs files?

Q. I am new to Linux and I would like to know where are the log files located under Debian or Cento OS Linux server? How do I open or view log files? Ans. Almost all logfiles are located under /var/log directory (and subdirectory). You can change to this directory using cd command but you need to be the root user. You can use less, more, cat or tail command to see the logs. Go to /var/logs directory: ...

How do I rotate log files?

Q. How do I rotate log files under Linux operating system? A. You need use tool called logrotate, which is designed to ease administration of systems that generate large numbers of log files. It allows automatic rotation, compression, removal, and mailing of log files. Each log file may be handled daily, weekly, monthly, or when it grows too large. With this tool you keep logs longer with less disk space. Default configuration...

Redhat Enterprise Linux 5 / CentOS 5 monitor and track TCP connections on the network

Q. How do I track and monitor connection for eth1 public network interface under Redhat Enterprise Linux (RHEL) 5 server? Ans.You can use netstat command or tcptrack command. Both command can show established TCP connection and provides the ability to monitor the same....

BASIC LDAP CONFIGURATION For RHEL / Centos / Fedora

INTRO: LDAP stands for Lightweight Directory Access Protocol. It is used as centralized data (or Directory) server (not database server) for various purposes. There is a difference between Directory server and a Database server. In Directory server the data is read more frequently than it is written. In Database server the data is written more frequently than it is read. Here we shall see how LDAP is used for creating centralized...

Monday, September 3, 2012

Linux: Iptables Examples For New SysAdmins Part -->3

Before see this post please read my previous post (Linux: Iptables Examples For New SysAdmins Part -->2) #12: Log and Drop Packets   Type the following to log and block IP spoofing on public interface called eth1 # iptables -A INPUT -i eth1 -s 10.0.0.0/8 -j LOG --log-prefix "IP_SPOOF A: # iptables -A INPUT -i eth1 -s 10.0.0.0/8 -j DROP ...

Linux: Iptables Examples For New SysAdmins Part -->2

Before see this post please read my previous post (Linux: Iptables Examples For New SysAdmins Part -->1) #3: Delete Firewall Rules To display line number along with other information for existing rules, enter: # iptables -L INPUT  -n --line-numbers # iptables -L OUTPUT -n --line-numbers # iptables...

Linux: Iptables Examples For New SysAdmins Part -->1

Linux comes with a host based firewall called Netfilter. According to the official project site: netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack. This Linux based firewall is controlled by the program called iptables to...

Redhat / CentOS Iptables Firewall Configuration

H ow do I configure a host-based firewall called Netfilter (iptables) under CentOS / RHEL / Fedora / Redhat Enterprise Linux? Icon reference for Firewall Netfilter is a host-based firewall for Linux operating systems. It is included as part of the Linux distribution and it is activated...

What is sysctl.conf in Linux

sysctl is an interface that allows you to make changes to a running Linux kernel. With /etc/sysctl.conf you can configure various Linux networking and system settings such as: 1.      Limit network-transmitted configuration for IPv4 2.      Limit network-transmitted configuration for IPv6 3.      Turn on execshield protection 4.      Prevent...

Friday, August 31, 2012

Red Hat / CentOS VSFTPD FTP Server Configuration

Vsftpd (Very Secure FTP Daemon) is an FTP server for UNIX-like systems, including CentOS / RHEL / Fedora and other Linux distributions. It supports IPv6, SSL, locking users to their home directories and many other advanced features. In this guide you will learn: 1.                  Setup vsftpd to Provide FTP Service. 2.                  Configure...
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