Tuesday 30 July 2013

Solution: Bind Failed Permission Denied error in Linux

if you get Bind Failed Permission Denied error in Linux
for different application like "iperf" etc
Solution is :  Disable SeLinux


Below steps show how to disable SELINUX

To test SeLinux is running or not
[root@center /]# selinuxenabled && echo enabled || echo disabled
enabled

So SELINUX is Enabled

To stop temporary
[root@xyz~] sudo setenforce 0

To stop SELINUX permanently
[root@center /]# vim /etc/selinux/config

#And change
SELINUX=enforcing

to

SELINUX=disabled

Save the File and Restart the system to take effect
Read More

Monday 29 July 2013

How to Find File Location in Linux


This post explains How to Find File Location in Linux

Find file in home directory

[root@sys ~]# find /home -name "finename.txt"

Find file in entire system

[root@sys ~]# find / -name "filename.txt"

Find file containing perticular word example httpd

[root@sys ~]# find /etc -name "*httpd*"

Find files of perticular type example .pdf file or .jpg or .png etc

[root@sys ~]# find /home -name "*.pdf"
Read More

Unable to Login as root authentication failure error in Linux

If you get Unable to Login as root authentication failure error in Linux

Modify two files 

1. vi /etc/pam.d/gdm-password 
in this file put comment on line "auth        required      pam_succeed_if.so user != root quiet" like below

auth     [success=done ignore=ignore default=bad] pam_selinux_permit.so
auth        substack      password-auth
auth        required      pam_succeed_if.so user != root quiet
auth        optional      pam_gnome_keyring.so
.....
.....
To

auth     [success=done ignore=ignore default=bad] pam_selinux_permit.so
auth        substack      password-auth
#auth        required      pam_succeed_if.so user != root quiet
auth        optional      pam_gnome_keyring.so
....
...

2. vi /etc/pam.d/gdm-fingerprint
in this file put comment on line "auth        required      pam_succeed_if.so user != root quiet" like below

auth        substack      fingerprint-auth
auth        required      pam_succeed_if.so user != root quiet

account     required      pam_nologin.so
account     include       fingerprint-auth

password    include       fingerprint-auth
....
....
To

auth        substack      fingerprint-auth
#auth        required      pam_succeed_if.so user != root quiet

account     required      pam_nologin.so
account     include       fingerprint-auth

password    include       fingerprint-auth
....
....

3. Logout and Re-Login as root



Read More

Thursday 25 July 2013

Steps to Compile Linux Kernel with Different Configuration Options


Below Steps describe How to Compile Linux Kernel with Different Configuration Options
1. Download Kernel from https://www.kernel.org/ 
download tar.xz file Example:https://www.kernel.org/pub/linux/kernel/v3.x/linux-3.10.3.tar.xz
2. Extract tar.xz file
tar -xvf linux-3.10.3.tar.xz
3. Goto Extracted folder
cd linux-3.10.3
4. Configuration command is
make menuconfig
based on requirement you can choose different configuration options

"make config"      Plain text interface.
"make menuconfig"  Text based color menus, radiolists & dialogs.
"make xconfig"     X windows (Qt) based configuration tool.
"make gconfig"     X windows (Gtk) based configuration tool.
"make oldconfig"   Default all questions based on the contents of
  your existing ./.config file and asking about
  new config symbols.
"make silentoldconfig"
  Like above, but avoids cluttering the screen
  with questions already answered.
  Additionally updates the dependencies.
"make defconfig"   Create a ./.config file by using the default
  symbol values from either arch/$ARCH/defconfig
  or arch/$ARCH/configs/${PLATFORM}_defconfig,
  depending on the architecture.
"make ${PLATFORM}_defconfig"
 Create a ./.config file by using the default
 symbol values from
 arch/$ARCH/configs/${PLATFORM}_defconfig.
 Use "make help" to get a list of all available
 platforms of your architecture.
"make allyesconfig"
  Create a ./.config file by setting symbol
  values to 'y' as much as possible.
"make allmodconfig"
  Create a ./.config file by setting symbol
  values to 'm' as much as possible.
"make allnoconfig" Create a ./.config file by setting symbol
  values to 'n' as much as possible.
"make randconfig"  Create a ./.config file by setting symbol
  values to random values.

4. make
5. make modules
6. make modules_install
7. make install
8. Check /boot/grub/grub.conf file whether new kernel entry added or not
if it is not there try "update-grub" command
Read More

Wednesday 3 July 2013

Upgrade Fedora 18 to Fedora 19


Fedora 19 (release 03 July 2013) :

First we need fedup software to update the fedora 18 to fedora 19

1) install fedup software by yum

      #  yum -y install fedup

2) Now it time to start the update, before that close all applications ( because it reboot after downloading the packages ).  Using Fedup command we will update the fedora 18.

     #  fedup --network 19 --instrepo=http://fedora.mirror.nexicom.net/linux/releases/19/Fedora/i386/os


This command will start downloading the Fedora 19 packages and setup the update startup for the system. 

Here we are updating Fedora 18 32 bit  OS to Fedora 19 32 bit

If you have Fedora 18 64 bit  then change the instrepo url  as :
   
    #  fedup --network 19 --instrepo=http://fedora.mirror.nexicom.net/linux/releases/19/Fedora/x86_64/os


3) That is it will start download the all the packages required and reboot with fedup grub menu option and install the downloaded packages. It will reboot after completion.

    It start will fedora 19 Enjoy with less bugs.



4) There is bug in fedora19  grub2 theme for we nee to install grub2 theme software by yum

    # yum install grub2-starfield-theme

Read More
Here We Write The Problems we face at different situations and Solutions to those problems.