How to Reset GRUB Password in Linux

Here are the steps of changing / rest grub password even after loading the OS

(1) # grub
 grub> passwd: **********
 grub> Encripted: $1$CxcdNVbcfsgUEFd0

Now copy the password-hash ie Encrypted value

(2) Edit grub.conf file and paste the password-hash

# vi /etc/grub.conf

passwd --md5 $1$CxcdNVbcfsgUEFd0

(3) Now save the file and restart the system.

How to Reset The Root Password in Linux

This blog post illustrates three methods to break the root/grub password

METHOD 1

HOW TO RESET UR ROOT PASSWORD IF U FORGET IT

While Booting ( Redhat ) just press "e" in GRUB

u will find 3 lines of code.

Goto to the 2nd line press "e" again and type "1" in the end

then press ENTER.

Then press "b" and it will boot you into your shell.

Just type "passwd" and change your ROOT password...

don't need to know the old one.


METHOD 2

"I, uh, forgot the root password"

Let's look at recovering the root password from the boot loader. If you're using GRUB, then, as GRUB loads up, highlight the Red Hat Linux entry on the GRUB menu and then press [E] to edit the boot configuration. Locate the following line, something that looks like this:

kernel /boot/vmlinuz-2.4.20-0.70 root=LABEL=/hdc=ide-scsi

Type the number '1' at the end. Doing so boots the PC into run level 1-single user mode, where you're automatically logged in as root. This done, type 'passwd' at the prompt. You can enter a new password here.


METHOD 3

To break the GRUB start-up password, follow the steps given below:

1. Boot the system with the first Linux CD. At the boot prompt, type linux rescue to switch to rescue mode. In rescue mode you will be asked if similar steps should be followed, which need to be followed in the installation. Once you get the # prompt, type the following command:

# chmod /mnt/sysImage

2. Edit the grub.conf file and remove the passwd line from the file. Save the file and exit.

3. Once your machine reboots, you will be able to start your Linux OS in the usual manner.

How To Install RHEL on SATA HDD

During the installation of Linux (RHEL) on a SATA HDD, it can give PCI Probing Error and/or disk error.

Two changes must be done before loading the RHEL on a SATA disk.

(1) In BIOS:

In advance option change SATA as IDE

(2) Insert CD-1 and type the following line on boot: prompt-

boot: linux pci=nommconf
or
boot: linux all-generic-ide noapic nolapic
or
boot: linux all-generic-ide
or
boot: linux nommconf all-generic-ide
or
boot: apm=off acpi=off

Now you can load RHEL-5 on your SATA HDD.

How To Install Printers in Linux / Ubuntu

Here is the procedure to install the printer with the Zenographics ZjStream wire protocol.

There are many printers that use the Zenographics engine. I have compiled a list below:


Printer Model                          foo2zjs Identifier

HP Color LaserJet 2600n                2600n

HP Color LaserJet 1600                 1600

Konica Minolta magicolor 2530DL 2530

Konica Minolta magicolor 2490MF 2490

Konica Minolta magicolor 2480MF 2480

Xerox Phaser 6115MFP                 6115

Konica Minolta magicolor 2430 DL 2430

Minolta/QMS magicolor 2300 DL   2300

Minolta/QMS magicolor 2200 DL   2200

Minolta Color PageWorks/Pro L     cpwl

Samsung CLP-300                          300

Samsung CLP-600                          600

Samsung CLX-2160                       2160

Samsung CLX-3160                       3160

* Okidata 3200n                             3200

* Okidata 3300n                             3300

* Okidata 3400n                             3400

* Okidata 5100n                             5100

* Okidata 5200n                             5200

* Okidata 5500n                             5500

* Okidata 5600n                             5600

* Okidata 5800n                             5800

Xerox Phaser 6110 and 6110MFP 6110

Lexmark C500                               500

HP LaserJet 1020                          1020

HP LaserJet 1018                          1018

HP LaserJet 1005                          1005

HP LaserJet 1000                          1000

HP Laserjet P1005                        P1005

HP Laserjet P1006                        P1006

HP Laserjet P1505                        P1505
-------------------------------------------------------------------------------

PROCEDURE (A):-

(1) Download driver

$ wget -0 foo2zjs.tar.gz http://foo2zjs.rkkda.com/foo2zjs.tar.gz

(2) Unpack it

$ tar zxf foo2zjs.tar.gz
$ cd foo2zjs

(3) Compile it

$ make

(4) Get extra file and firmware

$ ./getweb 1020    # for e.g.  HP 1020 Printer

(5) Install driver

$ sudo make install
or
# make install

(6) Configure hot-plugins (optional)

# make install-hotplug

(7) Restart Spooler

# make cups

(8) Now Add a printer

# printconf-gui
---------------------------------------------------------------------------------

PROCEDURE (B):-

Download the script to your home folder (Ubuntu Feisty/Edgy/Dapper).


wget http://www.stchman.com/tools/foo2zjs/ubuntu_foo2zjs_install.sh

Download the script to your home folder (Ubuntu Gutsy)

wget http://www.stchman.com/tools/foo2zjs/ubuntu_foo2zjs_install_gutsy_hardy.sh

Change the permission to the executable on the script (Ubuntu Feisty/Edgy/Dapper).

chmod 755 ~/ubuntu_foo2zjs_install.sh

Change the permission to the executable on the script (Ubuntu Gutsy and Hardy).

chmod 755 ~/ubuntu_foo2zjs_install_gutsy_hardy.sh

Run the script with the proper foo2zjs Identifier.
It is imperative that you select the proper printer as the proper firmware needs to be loaded. Substitute with the proper number in column one from the chart above. If you have a Laserjet 1000 then substitute 1000 for. A number other than one from the chart will cause the script to terminate.
Ubuntu Feisty/Edgy/Dapper

sudo ~/ubuntu_foo2zjs_install.sh

Ubuntu Gutsy and Hardy

sudo ~/ubuntu_foo2zjs_install_gutsy_hardy.sh

The script will launch the Gnome CUPS Manager for Feisty/Edgy/Dapper or System Printer Configuration tool in Gutsy. Select your printer and follow the on-screen selections.

Remove the script as it is no longer needed.
The script will take care of removing the archive and all associated temporary files.

Ubuntu Feisty/Edgy/Dapper

rm -f ~/ubuntu_foo2zjs_install.sh

Ubuntu Gutsy and Hardy

rm -f ~/ubuntu_foo2zjs_install_gutsy_hardy.sh

Your Zenographics based printer should now function under Ubuntu as well as it does under Windows. Cycle power on the printer and reboot your computer.

Happy printing :)

Secure your system over the net

Make the following settings in your PC / Laptop for more secure net surfing. Here it is shown the screenshots of Windows XP. More or less it is the same for Windows 7 and Vista.

(1) Disable auto shares. Follow the link for more details;

How to disable auto shares

(2) Disable vulnerable ports. Follow the link for more detail;

How to disable TCP/UDP ports

(3) Disable Remote desktop

My Computer ->Properties ->Remote ->Remote Desktop then uncheck the checkbox.

(4) Do not log in as administrator while surfing the net.

How to install Java in Ubuntu /Linux

There are two methods to install JRE/JDK in Ubuntu
(1) Online:

#sudo apt-get install sun-java6-jre (for users)
#sudo apt-get install sun-java6-jdk (for developers)
#sudo apt-get install sun-java6-plugins (java plugins)
#sudo apt-get install sun-java6-fonts (java fonts)
Or you can run all commands together
#sudo apt-get install sun-java6-jre sun-java6-plugins sun-java6-jdk

(It will download JRE/JDK from Sun site and install in your system)

To check java version
#java -version

Or type in FireFox URL
about:plugins
It will display installed java plugins.

(2) Offline:

(a) Non -RPM package (bin)

(i) Download the JDK from Sun
(ii) Click on the "Download" link in the JDK 6 section.
(iii) Accept the license and continue.
(iv) Under the "Linux Platform", select "self-extracting file".
(v) Download this .bin file and save it to your GNU/Linux machine.
(vi) Once it has been downloaded, switch to the directory where you saved the file. You do not need to be a root and only must have the write access to the folder where you wish to install java. If your administrator is not supportive, you may need to place java into your home folder or even better on some shared network location.
(vii) Type sh name_of_the_downloaded_file, for instance sh jdk-6u2-linux-i586.bin. There is no need to make this file executable.
(viii) The license agreement should start to appear on the screen. Scroll to the end of it with 'Enter' and type yes.
(ix) This installer will create its installation in the same folder, where the downloaded file was placed and from where you have started the installation script. But the installed java jre is rather independent and can be easily moved into another place just by copying all its files.
(x) You can install multiple different jre's this way: they coexist together and can be used if some software requires the older version to run.
(xi) The java executable you need to launch is located in a subfolder, called 'bin'. This way of installation will not configure a default 'java' command for you: you must do this manually or always include the full path in your startup script.

(b) RPM package

(i) Download the JDK from Sun
(ii) Click on the "Download" link in the JDK 6 section.
(iii) Accept the license and continue.
(iv) Under the "Linux Platform", select "RPM in the self-extracting file".
(v) Download this .bin file and save it to your GNU/Linux machine.
(vi) Once it has been downloaded, login as root and switch to the directory where you saved the file.
(vii) Execute './filename', where filename is the name of the file that you downloaded. The filename might be very similar to jdk-6-linux-i586-rpm.bin depending on what the latest version is. You may have to make the file executable by executing the 'chmod +x filename.bin' command.
(viii) You will get a license, press space bar a bunch of times until you are prompted to enter yes or no. Type in yes and hit enter.
(ix) This will place a .rpm file in the same directory as your .bin file with the same name (minus the .bin part).(x) Install the rpm file by executing 'rpm -i filename.rpm', where filename is the name of your .rpm file. (Such as jdk-6-linux-i586.rpm).
(xi) Now, if you want to be able to execute this version of Java interpreter or compiler from any directory on your GNU/Linux system you will have to create a few symbolic links:

     ln -s /usr/java/jdk1.6.0/bin/java /usr/bin/java
     ln -s /usr/java/jdk1.6.0/bin/javac /usr/bin/javac

(xii) You are done :)

Blocking Blacklisted Sites In Windows And Linux/ Ubuntu

In Windows:

In Windows sites are restricted through browser settings or the firewall settings:
IE browser setting:
In the Menu bar select Tools -> Internet Options (as shown in fig-1)

(fig-1)

Now form Internet Options dialog select Security -> Restricted sites -> Sites
(as shown in fig-2)

(fig-2)

Now enter the URL of the blacklisted sites and click Add (as shown in fig-3)

(fig-3)

Now click close->Apply ->OK.

You can also make an entry in %systemroot%/system32/driver/etc/hosts file as below:
127.0.0.1       www.xyz.com

In Linux (Ubuntu /RHEL):

Its very simple to restrict a site in Linux based system.

gedit or vi /etc/hosts and make the following entry:

0.0.0.0     www.youtube.com (any site you want to restrict)
0.0.0.0     www.facebook.com

or

127.0.0.1   www.xyz.com

Find out Hardware configuration of Linux / Ubuntu based system

In Windows OS based system it's very easy to find out the system configuration by following commands:
(1) Run -> msinfo32
(2) Run ->cmd -> systeminfo
( You can even redirect the output from monitor to printer or a file by suffix the above command with > file_name.txt )

In RHEL or Ubuntu it's similarly easy too:

(I) Using /proc - there's important info located in this directory! cd /proc, then ls; use cat to read the files in /proc such as cpuinfo, devices, filesystems, meminfo, partitions, swaps, uptime, version, etc.; also, you can cd into the subdirectories in /proc, for example, cd driver
(1)# cat/proc/cpuinfo >cpu.txt
(2)# cat/proc/meminfo >mem.txt
(3)# cat/proc/swaps >swap.txt
(4)# cat/proc/version >ver.txt

(II) Using dmidecode (for memery)
# dmidecode | less
or
# dmidecode >dmi.txt
or
# dmidecode -t memory
or
# dmidecode --type 17

How To Disable User Access Control (UAC) Popups in Windows

"Windows needs your permissions to continue."

User Account Control can be annoying, but you should think twice before disabling it. UAC's pop-ups make it simpler to use a standard Vista account since you can temporarily elevate to an administrator account by typing a password. Using a standard user account helps to protect your computer from attack since malware's impact can be limited when not running with administrator rights.
If you still want to disable UAC popups, follow these instructions to disable User Account Control.

(a) Type "user account" into the Windows Vista Start menu and click on User Account when it appears in the Programs list.

(b) Click on the Turn User Account Control on or off-link.

(c) If UAC is currently turned on, you will be prompted for approval. Provide the administrator's password or click Continue if you are sure you want to turn UAC off.

(d) This isn't a time when you should just blindly dismiss the UAC prompt. It's best to use a standard account for your general computing and provide an administrator's password when UAC prompts. It helps protect your computer from attack. If you do turn off UAC, seriously consider the implications and think about turning it back on as soon as possible.

 (e) Uncheck the box next to Use User Account Control (UAC) to help protect your computer to disable UAC. Click OK to save your changes.

Windows 7/8 Secuity Settings

Introduction

1. The flexibility and convenience of Windows-based Operating System (OS) has resulted in being a widely used desktop environment. It is essential to use these desktop environments in a secure manner to avoid exploitation of the possible vulnerability of the OS. This article explains how to configure the security settings in Windows Operating System.

Windows Security Center

2. The Windows Security Center in Windows 8 /Windows 7 lets you view and change important security settings. It monitors your settings and notifies you if there is a problem. It is intended to serve as a hub to your computer's security settings, making it easier to understand what you need to do to keep your computer secure. Although you can choose settings other than those recommended, the Center helps you know when your settings are different from those suggested by Microsoft.

3. The control panel for the Windows Security Center organizes security settings into four categories for easy viewing. A green background indicates the category's settings are optimal, yellow indicates the settings may need attention, and red indicates a problem likely exists.

4. The easiest way to open the Windows Security Center is to type "security center" into the search box integrated into the Vista Start menu. The list of programs will be filtered down to only the Security Center, and you can start it by clicking the link or pressing Enter. You can also access the Security Center through the Windows Vista Control Panel. 5. Click on one of the links below to learn about the security settings Windows Security Center monitors.

Firewall
 
6. The firewall category in the Windows Security Center lets you see if Windows Firewall is on. Windows Firewall is a free firewall included in Windows Vista that can prevent unwanted access to your computer.

7. If you turn it off, Windows Security Center will draw your attention to the problem by changing the background of the category heading to red. A button makes it easy to turn Windows firewall on, or you can click on the Windows Firewall link in the left panel to change the Windows firewall settings
 
Automatic Updating
 
8. The automatic updating category of the Windows Security Center lets you easily see if your computer is configured to automatically download and install security and other updates from Microsoft. If your computer isn't configured for automatic updates, a button to change the settings is provided. You can also click the Windows Update link in the left panel to change your settings.
 
Malware Protection
 
9. The malware protection category in the Windows Security Center monitors your use of antivirus and other anti-malware software. Windows Vista includes Windows Defender, a program that protects against spyware and other malware. Vista does not, however, include an antivirus program. The Windows Security Center makes it easy to see if you have the malware protection you need, and it provides links to help you purchase antivirus software and control Windows Defender.
 
Other Security Settings
 
10. Windows Security Center also monitors your Internet Explorer options and makes sure you have User Account Control turned on. The Internet Explorer options help to secure your computer and data from malicious Web sites while User Account Control prevents unwanted changes to your system.