How to Configure NTP Server for Time Adjustment on CentOS 6.3

ntpThis post covers the steps to install NTP server on CentOS 6.3. NTP, Network Time Protocol, it is an Internet protocol used to synchronize the clocks of computers or servers to some NTP server on internet or intranet.

1. Install ntp using yum command :

[root@centos63 ~]# yum install ntp -y

2. Once NTP is installed you need to update the configuration file, ntp.conf located in the /etc directory :

[root@centos63 ~]# vi /etc/ntp.conf
# Hosts on local network are less restricted.
restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#server 0.centos.pool.ntp.org
#server 1.centos.pool.ntp.org
#server 2.centos.pool.ntp.org
server 0.asia.pool.ntp.org
server 1.asia.pool.ntp.org
server 2.asia.pool.ntp.org
server 3.asia.pool.ntp.org

..
..

3. Start the NTP service :

[root@centos63 ~]# /etc/rc.d/init.d/ntpd start
Starting ntpd:                                             [  OK  ]

4. NTP service start at boot :

[root@centos63 ~]# chkconfig ntpd on

5. Test your ntp client status :

[root@centos63 ~]# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 103.6.16.254    10.84.87.146     2 u   16   64    1  129.453   18.233   0.002
 superluminal.sf 189.70.85.38     2 u   16   64    1  128.466    1.971   0.002
 fnttkyo043241.t 165.246.43.176   3 u   15   64    1  125.813   11.528   0.002
 send.mx.cdnetwo 131.107.13.100   2 u   14   64    1  250.371  -53.987   0.002

6. To verify the NTP service is now running on the server using the following command :

[root@centos63 ~]# ps -e | grep ntpd
 5206 ?        00:00:00 ntpd

How to Setup phpMyAdmin on CentOS 6.3 using EPEL Repository

phpmyadminThis post will covers the steps to install phpMyAdmin to operate MySQL from Web browser. phpMyAdmin is a free software tool written in PHP intended to handle the administration of MySQL over the World Wide Web. It can manage a whole MySQL server (needs a super-user) as well as a single database. phpMyAdmin supports a wide range of operations with MySQL. The most frequently used operations are supported by the user interface (managing databases, tables, fields, relations, indexes, users, permissions, etc), while you still have the ability to directly execute any SQL statement.

Prerequisites :

How to Configure EPEL Repository on CentOS 6.3
How to Install Httpd on CentOS 6.3
How to Install and Securing MySQL Database Server on CentOS 6.3

1. Install phpmyadmin :

[root@centos63 ~]# yum --enablerepo=epel install phpMyAdmin php-mysql php-mcrypt -y

Examples :

[root@centos63 ~]# yum --enablerepo=epel install phpMyAdmin php-mysql php-mcrypt -y
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
 * base: mirror.issp.co.th
 * epel: mirror.nus.edu.sg
 * extras: mirror.issp.co.th
 * updates: mirror.issp.co.th
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package php-mcrypt.i686 0:5.3.3-1.el6 will be installed
--> Processing Dependency: php-api = 20090626 for package: php-mcrypt-5.3.3-1.el6.i686
--> Processing Dependency: libmcrypt.so.4 for package: php-mcrypt-5.3.3-1.el6.i686
---> Package php-mysql.i686 0:5.3.3-14.el6_3 will be installed
--> Processing Dependency: php-pdo for package: php-mysql-5.3.3-14.el6_3.i686
---> Package phpMyAdmin.noarch 0:3.5.1-1.el6 will be installed
--> Processing Dependency: php-mbstring >= 5.2.0 for package: phpMyAdmin-3.5.1-1.el6.noarch
--> Processing Dependency: php-gd >= 5.2.0 for package: phpMyAdmin-3.5.1-1.el6.noarch
--> Processing Dependency: php >= 5.2.0 for package: phpMyAdmin-3.5.1-1.el6.noarch
--> Processing Dependency: php-php-gettext for package: phpMyAdmin-3.5.1-1.el6.noarch
--> Running transaction check
---> Package libmcrypt.i686 0:2.5.8-9.el6 will be installed
---> Package php.i686 0:5.3.3-14.el6_3 will be installed
--> Processing Dependency: php-cli = 5.3.3-14.el6_3 for package: php-5.3.3-14.el6_3.i686
---> Package php-common.i686 0:5.3.3-14.el6_3 will be installed
---> Package php-gd.i686 0:5.3.3-14.el6_3 will be installed
--> Processing Dependency: libpng12.so.0(PNG12_0) for package: php-gd-5.3.3-14.el6_3.i686
--> Processing Dependency: libpng12.so.0 for package: php-gd-5.3.3-14.el6_3.i686
--> Processing Dependency: libjpeg.so.62 for package: php-gd-5.3.3-14.el6_3.i686
--> Processing Dependency: libfreetype.so.6 for package: php-gd-5.3.3-14.el6_3.i686
--> Processing Dependency: libXpm.so.4 for package: php-gd-5.3.3-14.el6_3.i686
--> Processing Dependency: libX11.so.6 for package: php-gd-5.3.3-14.el6_3.i686
---> Package php-mbstring.i686 0:5.3.3-14.el6_3 will be installed
---> Package php-pdo.i686 0:5.3.3-14.el6_3 will be installed
---> Package php-php-gettext.noarch 0:1.0.11-3.el6 will be installed
--> Running transaction check
---> Package freetype.i686 0:2.3.11-6.el6_2.9 will be installed
---> Package libX11.i686 0:1.3-2.el6 will be installed
--> Processing Dependency: libX11-common = 1.3-2.el6 for package: libX11-1.3-2.el6.i686
--> Processing Dependency: libxcb.so.1 for package: libX11-1.3-2.el6.i686
---> Package libXpm.i686 0:3.5.8-2.el6 will be installed
---> Package libjpeg.i686 0:6b-46.el6 will be installed
---> Package libpng.i686 2:1.2.49-1.el6_2 will be installed
---> Package php-cli.i686 0:5.3.3-14.el6_3 will be installed
--> Running transaction check
---> Package libX11-common.noarch 0:1.3-2.el6 will be installed
---> Package libxcb.i686 0:1.5-1.el6 will be installed
--> Processing Dependency: libXau.so.6 for package: libxcb-1.5-1.el6.i686
--> Running transaction check
---> Package libXau.i686 0:1.0.5-1.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================
 Package                 Arch           Version                  Repository                    Size
====================================================================================================
Installing:
 php-mcrypt              i686           5.3.3-1.el6              epel                          18 k
 php-mysql               i686           5.3.3-14.el6_3           updates                       77 k
 phpMyAdmin              noarch         3.5.1-1.el6              epel                         4.2 M
Installing for dependencies:
 freetype                i686           2.3.11-6.el6_2.9         CentOS6.3-Repository         363 k
 libX11                  i686           1.3-2.el6                CentOS6.3-Repository         585 k
 libX11-common           noarch         1.3-2.el6                CentOS6.3-Repository         188 k
 libXau                  i686           1.0.5-1.el6              CentOS6.3-Repository          22 k
 libXpm                  i686           3.5.8-2.el6              CentOS6.3-Repository          58 k
 libjpeg                 i686           6b-46.el6                CentOS6.3-Repository         133 k
 libmcrypt               i686           2.5.8-9.el6              epel                          94 k
 libpng                  i686           2:1.2.49-1.el6_2         CentOS6.3-Repository         184 k
 libxcb                  i686           1.5-1.el6                CentOS6.3-Repository         104 k
 php                     i686           5.3.3-14.el6_3           updates                      1.1 M
 php-cli                 i686           5.3.3-14.el6_3           updates                      2.2 M
 php-common              i686           5.3.3-14.el6_3           updates                      523 k
 php-gd                  i686           5.3.3-14.el6_3           updates                      103 k
 php-mbstring            i686           5.3.3-14.el6_3           updates                      453 k
 php-pdo                 i686           5.3.3-14.el6_3           updates                       72 k
 php-php-gettext         noarch         1.0.11-3.el6             epel                          21 k

Transaction Summary
====================================================================================================
Install      19 Package(s)

Total download size: 10 M
Installed size: 38 M
Downloading Packages:
Setting up and reading Presto delta metadata
updates/prestodelta                                                          |  72 kB     00:00
Processing delta metadata
Package(s) data still to download: 10 M
(1/19): libmcrypt-2.5.8-9.el6.i686.rpm                                       |  94 kB     00:00
(2/19): php-5.3.3-14.el6_3.i686.rpm                                          | 1.1 MB     00:09
(3/19): php-cli-5.3.3-14.el6_3.i686.rpm                                      | 2.2 MB     00:19
(4/19): php-common-5.3.3-14.el6_3.i686.rpm                                   | 523 kB     00:04
(5/19): php-gd-5.3.3-14.el6_3.i686.rpm                                       | 103 kB     00:00
(6/19): php-mbstring-5.3.3-14.el6_3.i686.rpm                                 | 453 kB     00:04
(7/19): php-mcrypt-5.3.3-1.el6.i686.rpm                                      |  18 kB     00:00
(8/19): php-mysql-5.3.3-14.el6_3.i686.rpm                                    |  77 kB     00:00
(9/19): php-pdo-5.3.3-14.el6_3.i686.rpm                                      |  72 kB     00:00
(10/19): php-php-gettext-1.0.11-3.el6.noarch.rpm                             |  21 kB     00:00
(11/19): phpMyAdmin-3.5.1-1.el6.noarch.rpm                                   | 4.2 MB     00:36
----------------------------------------------------------------------------------------------------
Total                                                               135 kB/s |  10 MB     01:19
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : php-common-5.3.3-14.el6_3.i686                                                  1/19
  Installing : libX11-common-1.3-2.el6.noarch                                                  2/19
  Installing : php-mbstring-5.3.3-14.el6_3.i686                                                3/19
  Installing : php-php-gettext-1.0.11-3.el6.noarch                                             4/19
  Installing : php-cli-5.3.3-14.el6_3.i686                                                     5/19
  Installing : php-5.3.3-14.el6_3.i686                                                         6/19
  Installing : php-pdo-5.3.3-14.el6_3.i686                                                     7/19
  Installing : php-mysql-5.3.3-14.el6_3.i686                                                   8/19
  Installing : libmcrypt-2.5.8-9.el6.i686                                                      9/19
  Installing : php-mcrypt-5.3.3-1.el6.i686                                                    10/19
  Installing : libjpeg-6b-46.el6.i686                                                         11/19
  Installing : 2:libpng-1.2.49-1.el6_2.i686                                                   12/19
  Installing : libXau-1.0.5-1.el6.i686                                                        13/19
  Installing : libxcb-1.5-1.el6.i686                                                          14/19
  Installing : libX11-1.3-2.el6.i686                                                          15/19
  Installing : libXpm-3.5.8-2.el6.i686                                                        16/19
  Installing : freetype-2.3.11-6.el6_2.9.i686                                                 17/19
  Installing : php-gd-5.3.3-14.el6_3.i686                                                     18/19
  Installing : phpMyAdmin-3.5.1-1.el6.noarch                                                  19/19
  Verifying  : freetype-2.3.11-6.el6_2.9.i686                                                  1/19
  Verifying  : php-5.3.3-14.el6_3.i686                                                         2/19
  Verifying  : php-cli-5.3.3-14.el6_3.i686                                                     3/19
  Verifying  : libXau-1.0.5-1.el6.i686                                                         4/19
  Verifying  : php-common-5.3.3-14.el6_3.i686                                                  5/19
  Verifying  : php-mbstring-5.3.3-14.el6_3.i686                                                6/19
  Verifying  : libXpm-3.5.8-2.el6.i686                                                         7/19
  Verifying  : 2:libpng-1.2.49-1.el6_2.i686                                                    8/19
  Verifying  : libxcb-1.5-1.el6.i686                                                           9/19
  Verifying  : phpMyAdmin-3.5.1-1.el6.noarch                                                  10/19
  Verifying  : libX11-1.3-2.el6.i686                                                          11/19
  Verifying  : php-php-gettext-1.0.11-3.el6.noarch                                            12/19
  Verifying  : php-gd-5.3.3-14.el6_3.i686                                                     13/19
  Verifying  : libjpeg-6b-46.el6.i686                                                         14/19
  Verifying  : libX11-common-1.3-2.el6.noarch                                                 15/19
  Verifying  : php-mysql-5.3.3-14.el6_3.i686                                                  16/19
  Verifying  : php-pdo-5.3.3-14.el6_3.i686                                                    17/19
  Verifying  : php-mcrypt-5.3.3-1.el6.i686                                                    18/19
  Verifying  : libmcrypt-2.5.8-9.el6.i686                                                     19/19

Installed:
  php-mcrypt.i686 0:5.3.3-1.el6  php-mysql.i686 0:5.3.3-14.el6_3  phpMyAdmin.noarch 0:3.5.1-1.el6

Dependency Installed:
  freetype.i686 0:2.3.11-6.el6_2.9               libX11.i686 0:1.3-2.el6
  libX11-common.noarch 0:1.3-2.el6               libXau.i686 0:1.0.5-1.el6
  libXpm.i686 0:3.5.8-2.el6                      libjpeg.i686 0:6b-46.el6
  libmcrypt.i686 0:2.5.8-9.el6                   libpng.i686 2:1.2.49-1.el6_2
  libxcb.i686 0:1.5-1.el6                        php.i686 0:5.3.3-14.el6_3
  php-cli.i686 0:5.3.3-14.el6_3                  php-common.i686 0:5.3.3-14.el6_3
  php-gd.i686 0:5.3.3-14.el6_3                   php-mbstring.i686 0:5.3.3-14.el6_3
  php-pdo.i686 0:5.3.3-14.el6_3                  php-php-gettext.noarch 0:1.0.11-3.el6

Complete!

2. on Line 14 or 15, add IP address you permit. In this case i have added 192.168.1.0/24 and i’m using apache 2.2 :

[root@centos63 ~]# vi /etc/httpd/conf.d/phpMyAdmin.conf
<Directory /usr/share/phpMyAdmin/>
   <IfModule mod_authz_core.c>
     # Apache 2.4
     <RequireAny>
       Require ip 127.0.0.1
       Require ip ::1
     </RequireAny>
   </IfModule>
   <IfModule !mod_authz_core.c>
     # Apache 2.2
     Order Deny,Allow
     Deny from All
     Allow from 127.0.0.1 192.168.1.0/24
     Allow from ::1
   </IfModule>
</Directory>

3. Reload or restart apache httpd :

[root@centos63 ~]# /etc/rc.d/init.d/httpd reload
Reloading httpd:

How to Configure EPEL Repository on CentOS 6.3

This post will covers on how to install and configure the Extra Packages for Enterprise Linux (EPEL) repository on CentOS 6.3. EPEL repository is another extra repository that creates, maintains, and manages a high quality set of additional packages for Enterprise Linux, including, but not limited to, Red Hat Enterprise Linux (RHEL) and CentOS server. To install the repository, you can follow this steps :

1. First, we download and import the GPG keys for EPEL software packages:

[root@centos63 ~]# wget http://ftp.riken.jp/Linux/fedora/epel/RPM-GPG-KEY-EPEL-6
[root@centos63 ~]# rpm --import RPM-GPG-KEY-EPEL-6
[root@centos63 ~]# rm -f RPM-GPG-KEY-EPEL-6

2. Download EPEL repository for 32-bit CentOS :

[root@centos63 ~]# wget http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-7.noarch.rpm

3. Install EPEL repository on 32-bit CentOS :

[root@centos63 ~]# rpm -ivh epel-release-6-7.noarch.rpm
Preparing...                ########################################### [100%]
   1:epel-release           ########################################### [100%]

4. You can start install and use epel the repository to install the software packages, input yum command like follows :

[root@centos63 ~]# yum --enablerepo=epel install phpmyadmin -y

How to Install Clam Antivirus on CentOS 6.3

ClamAVClamAV is an open source (GPL) antivirus engine designed for detecting Trojans, viruses, malware and other malicious threats. It provides a high performance mutli-threaded scanning daemon, command line utilities for on demand file scanning, and an intelligent tool for automatic signature updates. In this post, i will show how to install Clam Antivirus on CentOS 6.3. Clam Antivirus daemon named is clamd.

Run the following command to install Clam Antivirus :

[root@centos63 ~]# yum install clamd -y

Examples :

[root@centos63 ~]# yum install clamd -y
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
 * base: mirrors.hostemo.com
 * extras: mirrors.hostemo.com
 * rpmforge: mirror.oscc.org.my
 * updates: mirrors.hostemo.com
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package clamd.i686 0:0.97.5-2.el6.rf will be installed
--> Processing Dependency: clamav = 0.97.5-2.el6.rf for package: clamd-0.97.5-2.el6.rf.i686
--> Processing Dependency: libclamav.so.6 for package: clamd-0.97.5-2.el6.rf.i686
--> Processing Dependency: libclamav.so.6(CLAMAV_PRIVATE) for package: clamd-0.97.5-2.el6.rf.i686
--> Processing Dependency: libclamav.so.6(CLAMAV_PUBLIC) for package: clamd-0.97.5-2.el6.rf.i686
--> Running transaction check
---> Package clamav.i686 0:0.97.5-2.el6.rf will be installed
--> Processing Dependency: clamav-db for package: clamav-0.97.5-2.el6.rf.i686
--> Processing Dependency: libltdl.so.7 for package: clamav-0.97.5-2.el6.rf.i686
--> Running transaction check
---> Package clamav-db.i686 0:0.97.5-2.el6.rf will be installed
---> Package libtool-ltdl.i686 0:2.2.6-15.5.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================
 Package               Arch          Version                    Repository                     Size
====================================================================================================
Installing:
 clamd                 i686          0.97.5-2.el6.rf            rpmforge                      148 k
Installing for dependencies:
 clamav                i686          0.97.5-2.el6.rf            rpmforge                      1.9 M
 clamav-db             i686          0.97.5-2.el6.rf            rpmforge                       34 M
 libtool-ltdl          i686          2.2.6-15.5.el6             CentOS6.3-Repository           45 k

Transaction Summary
====================================================================================================
Install       4 Package(s)

Total download size: 36 M
Installed size: 40 M
Downloading Packages:
Setting up and reading Presto delta metadata
Processing delta metadata
Package(s) data still to download: 36 M
(1/4): clamav-0.97.5-2.el6.rf.i686.rpm                                       | 1.9 MB     00:17
(2/4): clamav-db-0.97.5-2.el6.rf.i686.rpm                                    |  34 MB     05:17
(3/4): clamd-0.97.5-2.el6.rf.i686.rpm                                        | 148 kB     00:01
----------------------------------------------------------------------------------------------------
Total                                                               111 kB/s |  36 MB     05:36
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
  Installing : clamav-db-0.97.5-2.el6.rf.i686                                                   1/4
  Installing : libtool-ltdl-2.2.6-15.5.el6.i686                                                 2/4
  Installing : clamav-0.97.5-2.el6.rf.i686                                                      3/4
  Installing : clamd-0.97.5-2.el6.rf.i686                                                       4/4
  Verifying  : libtool-ltdl-2.2.6-15.5.el6.i686                                                 1/4
  Verifying  : clamav-db-0.97.5-2.el6.rf.i686                                                   2/4
  Verifying  : clamav-0.97.5-2.el6.rf.i686                                                      3/4
  Verifying  : clamd-0.97.5-2.el6.rf.i686                                                       4/4

Installed:
  clamd.i686 0:0.97.5-2.el6.rf

Dependency Installed:
  clamav.i686 0:0.97.5-2.el6.rf clamav-db.i686 0:0.97.5-2.el6.rf libtool-ltdl.i686 0:2.2.6-15.5.el6

Complete!

How to Configure RPMforge Repository on CentOS 6.3

centos6RPMforge repository is a collaboration of Dag, Dries, and other packagers. The default RPMforge repository does not replace any CentOS base packages. This post covers the steps to configure RPMforge repository on linux CentOS 6.3. This steps has been tested on CentOS 6.3 and should be working on Redhat linux Enterprise 6.

1. Download the rpmforge-release package and DAG’s GPG key :

[root@centos63 ~]# wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.i686.rpm
[root@centos63 ~]# wget wget http://apt.sw.be/RPM-GPG-KEY.dag.txt

2. Install DAG’s GPG key :

[root@centos63 ~]# rpm --import RPM-GPG-KEY.dag.txt

3. Verify the rpmforge-release package that you have downloaded :

[root@centos63 ~]# rpm -K rpmforge-release-0.5.2-2.el6.rf.i686.rpm
rpmforge-release-0.5.2-2.el6.rf.i686.rpm: (sha1) dsa sha1 md5 gpg OK

4. If ok, proceed to install the rpmforge-release package using this command :

[root@centos63 ~]# rpm -ivh rpmforge-release-0.5.2-2.el6.rf.i686.rpm
Preparing...                ########################################### [100%]
   1:rpmforge-release       ########################################### [100%]

5. Proceed to configure RPMforge repository. Open the RPMforge configuration file and insert “priority=3” after “enabled = 1” in the [rpmforge] section as below :

[root@centos63 ~]# vi /etc/yum.repos.d/rpmforge.repo
### Name: RPMforge RPM Repository for RHEL 6 - dag
### URL: http://rpmforge.net/
[rpmforge]
name = RHEL $releasever - RPMforge.net - dag
baseurl = http://apt.sw.be/redhat/el6/en/$basearch/rpmforge
mirrorlist = http://apt.sw.be/redhat/el6/en/mirrors-rpmforge
#mirrorlist = file:///etc/yum.repos.d/mirrors-rpmforge
enabled = 1
priority = 3
protect = 0
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-dag
gpgcheck = 1

[rpmforge-extras]
name = RHEL $releasever - RPMforge.net - extras
baseurl = http://apt.sw.be/redhat/el6/en/$basearch/extras
mirrorlist = http://apt.sw.be/redhat/el6/en/mirrors-rpmforge-extras
#mirrorlist = file:///etc/yum.repos.d/mirrors-rpmforge-extras
enabled = 0
protect = 0
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-dag
gpgcheck = 1

[rpmforge-testing]
name = RHEL $releasever - RPMforge.net - testing
baseurl = http://apt.sw.be/redhat/el6/en/$basearch/testing
mirrorlist = http://apt.sw.be/redhat/el6/en/mirrors-rpmforge-testing
#mirrorlist = file:///etc/yum.repos.d/mirrors-rpmforge-testing
enabled = 0
protect = 0
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-dag
gpgcheck = 1

6. Check the updated repository list in /etc/yum.repos.d using the following command :

[root@centos63 ~]# yum repolist
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
 * base: mirrors.hostemo.com
 * extras: mirrors.hostemo.com
 * rpmforge: mirror.oscc.org.my
 * updates: mirrors.hostemo.com
repo id                                    repo name                                          status
CentOS6.3-Repository                       DVD-CentOS6.3 repository                           4,776
base                                       CentOS-6 - Base                                    4,776
extras                                     CentOS-6 - Extras                                      4
rpmforge                                   RHEL 6 - RPMforge.net - dag                        4,448
updates                                    CentOS-6 - Updates                                   202
repolist: 14,206

7. You can start using RPMforge Repository on your RHEL 6 or CentOS 6 linux server :

[root@centos63 ~]# yum install clamd -y

Insanity: Google Sends New Link Warnings, Then Says You Can Ignore Them

Google’s war on bad links officially became insane today. For months, Google’s sending out warnings about bad links and telling publishers they should act on those, lest they get penalized. Today, Google said the latest round of warnings sent out this week can be safely ignored. That’s not “more transparency” as Google posted. That’s more confusion.

It’s easiest to do the history first, to better understand the confusion caused by today’s post.

How We Got Here: Link Warnings Earlier This Year

Toward the end of March and in early April, Google began sending out warnings about “artificial” or “unnatural” links, such like this one:

Dear site owner or webmaster of….We’ve detected that some of your site’s pages may be using techniques that are outside Google’s Webmaster Guidelines.

Specifically, look for possibly artificial or unnatural links pointing to your site that could be intended to manipulate PageRank. Examples of unnatural linking could include buying links to pass PageRank or participating in link schemes.

We encourage you to make changes to your site so that it meets our quality guidelines. Once you’ve made these changes, please submit your site for reconsideration in Google’s search results.

If you find unnatural links to your site that you are unable to control or remove, please provide the details in your reconsideration request.

If you have any questions about how to resolve this issue, please see our Webmaster Help Forum for support.

Sincerely, Google Search Quality Team

There was some confusion about whether these messages meant that a site was actually penalized for having these links pointing at them or whether Google was just informing the sites but not really taking any negative action. Google’s response on this wasn’t clear:

Google has been able to trace and take action on many types of link networks; we recently decided to make that action more visible.In the past, some links might have been silently distrusted or might not have carried as much weight. More recently, we’ve been surfacing the fact that those links aren’t helping to improve ranking or indexing.

The Penguin Attacks

In late April, the Google Penguin Update went live. Designed to fight spam, it especially seemed to take action by either penalizing publishers who had participated in bad linking activities (as determined by Google’s) or discounting those links, so they no longer carried as much weight.

All hell broke loose in some quarters, especially among those who had been actively using link networks to boost their rankings in ways that went against Google’s guidelines. One of the suggested recovery options from Google was to remove bad links.

Google Advice: Get Rid Of Bad Links

But what if people couldn’t get links taken down? The head of Google’s web spam team, Matt Cutts, just generally suggested such a thing was possible without giving any specific advice.

This led further support to those who argued that “negative SEO” was now suddenly a real possibility, that any publisher could be targeted with “bad links” and made to plunge in Google’s rankings. Google stressed that negative SEO in this way is rare and hard. To this date, negative SEO still hasn’t seemed to be a wide-spread problem for the vast majority of publishers on the web.

Those reassurances — along with a Google help page update saying Google “works hard to prevent” negative SEO — hasn’t calmed some. Negative SEO has remained a rallying cry especially for many hit by Penguin (and many were deservedly hit) looking for a way to fight back against Google.

The New Link Building: Remove My Link Requests

But aside from the negative SEO sideshow, plenty of publishers tried to follow Google’s advice to get links removed. I’ve even had one come to me, from some publisher who was listed in our SearchCap daily newsletter in the past and wanted us to pull down a link. Insane. A link from a reputable site like ours is exactly what you want, and yet they wanted it removed.

The insanity has gotten even worse. We’ve had people threatening to sue to have links removed. We’ve covered that before. Boing Boing also covered another case today (without providing any of the background on how Google itself has fueled some of this craziness).

Today, we covered how some directories are now charging people to have links removed. Let’s be really clear on how topsy-turvey that means things have become. People have wanted links in the past and have been willing to pay for them (despite this being against Google’s rules). Now they’re perhaps willing to pay to have links taken down.

June: Google Says Don’t Ignore Link Warnings

But you’ve got to get those links removed, if you’ve gotten a warning message. After all, Google has said that. In June, at our SMX Advanced conference, Cutts said this about those link warnings:

You should pay attention. Typically your web site ranking will drop if you don’t take action after you get one of those notices.

Here’s the extended video clip on the topic:

But again, what to do if you can’t get links removed? Cutts said that Google might release a “disavow” tool. By the end of June, Bing even did launch such a link disavow tool — not that it helped with Google, of course. Those who had notices from Google about bad links pointing at them, notices they were supposed to take action on, still might not be able to get those links removed.

New Batch Of Warnings Goes Out

That leads to yesterday, when Google began sending out a new batch of link notices. Here’s an example of what one of those looks like:

Dear site owner or webmaster of….We’ve detected that some of your site’s pages may be using techniques that are outside Google’s Webmaster Guidelines.

Specifically, look for possibly artificial or unnatural links pointing to your site that could be intended to manipulate PageRank. Examples of unnatural linking could include buying links to pass PageRank or participating in link schemes.

We encourage you to make changes to your site so that it meets our quality guidelines. Once you’ve made these changes, please submit your site for reconsideration in Google’s search results.

If you find unnatural links to your site that you are unable to control or remove, please provide the details in your reconsideration request.

If you have any questions about how to resolve this issue, please see our Webmaster Help Forum for support.

Sincerely, Google Search Quality Team

Yes, that’s exactly the same content as what Google sent in late March. Nothing in the message gives the impression it can be ignored. It even encourages people who can’t get links removed to actively file a reconsideration request with Google.

July: Google Says You Can Ignore Link Warnings

But today, Cutts said this about the messages in a Google+ post:

If you received a message yesterday about unnatural links to your site, don’t panic. In the past, these messages were sent when we took action on a site as a whole.Yesterday, we took another step towards more transparency and began sending messages when we distrust some individual links to a site. While it’s possible for this to indicate potential spammy activity by the site, it can also have innocent reasons.

For example, we may take this kind of targeted action to distrust hacked links pointing to an innocent site. The innocent site will get the message as we move towards more transparency, but it’s not necessarily something that you automatically need to worry about.

If we’ve taken more severe action on your site, you’ll likely notice a drop in search traffic, which you can see in the “Search queries” feature Webmaster Tools for example.

As always, if you believe you have been affected by a manual spam action and your site no longer violates the Webmaster Guidelines, go ahead and file a reconsideration request. It’ll take some time for us to process the request, but you will receive a followup message confirming when we’ve processed it.

Like I said, this latest round of messages doesn’t seem to make things more transparent. The messages seem to be the same exact ones that Google previously told people they SHOULD worry about.

How About Just Saying If There’s A Real Concern

How do you know if you’re at risk if you get one of these new messages? Apparently, you also need to look at your traffic from Google and see if there’s a plunge. If so, you have a bad link problem. If not, well, you got a message that apparently can be ignored.

It would sure be much easier if the messages themselves said if action was really required or not. If there really was a penalty or not (in a world now where penalties that were penalties now might be “adjustments”).

That would be transparent. Instead, I predict this is all just going to cause greater confusion and panic, not more clarity and calmness.

It’s also yet another sign of how creaky the foundations or ranking sites based on links has become. It gets even more difficult these days to know what’s supposed to help or hurt. Links as votes suck.

Postscript: Google’s Matt Cutts commented below on Monday, July 23rd that the newer messages that can be safely ignored are now actually saying that:

An engineer worked over the weekend and starting with the messages that we sent out on Sunday, the messages are now different so that you can tell which type of situation you’re in. We also changed the UI in the webmaster console to remove the yellow caution sign for these newer messages. That reflects the fact that these newer notifications are much more targeted and don’t always require action by the site owner.

See also our follow-up story: Google Updates Link Warnings To (Sort Of) Clarify They Can Be Ignored (Maybe).

Read Full Article

How to Download CentOS 6.3 ISO

centos6Linux CentOS 6.3 has been released and available for the download. CentOS is a community-supported, mainly free software operating system based on Red Hat Enterprise Linux. It is an open source operating system distribution based upon the Linux kernel. In this post, i will share the recommended link to download latest CentOS 6.3 version.

Download 32 Bit :
Link 1
Link 2
Link 3

Download 64 Bit :
Link 1
Link 2
Link 3

How to Enable Admin Script of APC on PHP

On the previous post, i had shows how to enable APC with PHP on CentOS 6.3. This post will covers the steps to enable admin script of APC. The Alternative PHP Cache (APC) is a free, open, and robust framework for caching and optimizing PHP intermediate code. It’s an PECL extension which shares the packaging and distribution system with its sister, PEAR.

1. Create directory apc on document root :

[root@centos63 ~]# mkdir /var/www/html/apc

2. Copy apc.php from php-pecl-apc folder to document root :

[root@centos63 ~]# cp /usr/share/doc/php-pecl-apc-*/apc.php /var/www/html/apc

3. Create new file name apc.conf.php :

[root@centos63 ~]# vi /var/www/html/apc/apc.conf.php
<?php
   defaults('ADMIN_USERNAME','apcadmin');
# set any username

   defaults('ADMIN_PASSWORD','apcadmin');
# set any password

?>

4. Create new file name apc.conf :

[root@centos63 ~]# vi /etc/httpd/conf.d/apc.conf
<Directory /var/www/html/apc>
   Order Deny,Allow
   Deny from all
   Allow from 127.0.0.1 192.168.1.0/24
# IP address you allow

</Directory>

5. Restart Apache httpd :

[root@centos63 ~]# /etc/rc.d/init.d/httpd restart
Stopping httpd:                                            [  OK  ]
Starting httpd:                                            [  OK  ]

6. Navigate the browser to http://servername/apc/apc.php and it will shown as below :
Apc

How to Install Vim on CentOS 6.3

This post covers how to install Vim on linux CentOS 6.3. Vim is an alternative to vi editor. Meaning, vim is a text editor that is upwards compatible to Vi. Vim can be used to edit all kinds of plain text. It is especially useful for editing programs. This steps may working on other linux distribution as well.

Execute the following command to install Vim :

[root@centos63 ~]# yum install vim-enhanced -y

Examples :

[root@centos63 ~]# yum install vim-enhanced -y
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
 * base: mirrors.hostemo.com
 * extras: mirrors.hostemo.com
 * updates: mirrors.hostemo.com
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package vim-enhanced.i686 2:7.2.411-1.8.el6 will be installed
--> Processing Dependency: vim-common = 2:7.2.411-1.8.el6 for package: 2:vim-enhanced-7.2.411-1.8.el6.i686
--> Processing Dependency: libgpm.so.2 for package: 2:vim-enhanced-7.2.411-1.8.el6.i686
--> Running transaction check
---> Package gpm-libs.i686 0:1.20.6-12.el6 will be installed
---> Package vim-common.i686 2:7.2.411-1.8.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================
 Package               Arch          Version                    Repository                     Size
====================================================================================================
Installing:
 vim-enhanced          i686          2:7.2.411-1.8.el6          CentOS6.3-Repository          837 k
Installing for dependencies:
 gpm-libs              i686          1.20.6-12.el6              CentOS6.3-Repository           28 k
 vim-common            i686          2:7.2.411-1.8.el6          CentOS6.3-Repository          6.0 M

Transaction Summary
====================================================================================================
Install       3 Package(s)

Total download size: 6.8 M
Installed size: 19 M
Downloading Packages:
Setting up and reading Presto delta metadata
Processing delta metadata
Package(s) data still to download: 6.8 M
----------------------------------------------------------------------------------------------------
Total                                                                20 MB/s | 6.8 MB     00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : gpm-libs-1.20.6-12.el6.i686                                                      1/3
  Installing : 2:vim-common-7.2.411-1.8.el6.i686                                                2/3
  Installing : 2:vim-enhanced-7.2.411-1.8.el6.i686                                              3/3
  Verifying  : 2:vim-common-7.2.411-1.8.el6.i686                                                1/3
  Verifying  : 2:vim-enhanced-7.2.411-1.8.el6.i686                                              2/3
  Verifying  : gpm-libs-1.20.6-12.el6.i686                                                      3/3

Installed:
  vim-enhanced.i686 2:7.2.411-1.8.el6

Dependency Installed:
  gpm-libs.i686 0:1.20.6-12.el6                  vim-common.i686 2:7.2.411-1.8.el6

Complete!

To use vim, type vim instead of vi :

[root@centos63 ~]# vim /etc/httpd/conf/httpd.conf

How to Enable APC With PHP on CentOS 6.3

The Alternative PHP Cache (APC) is a free, open, and robust framework for caching and optimizing PHP intermediate code. It’s an PECL extension which shares the packaging and distribution system with its sister, PEAR. In this post, i will show how to enable APC (Alternative PHP Cache) and makes PHP be fast.

1. Install using yum command :

[root@centos63 ~]# yum install php-pecl-apc -y

Examples :

[root@centos63 ~]# yum install php-pecl-apc -y
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
 * base: mirrors.hostemo.com
 * extras: mirrors.hostemo.com
 * updates: mirrors.hostemo.com
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package php-pecl-apc.i686 0:3.1.9-2.el6 will be installed
--> Processing Dependency: /usr/bin/pecl for package: php-pecl-apc-3.1.9-2.el6.i686
--> Processing Dependency: /usr/bin/pecl for package: php-pecl-apc-3.1.9-2.el6.i686
--> Running transaction check
---> Package php-pear.noarch 1:1.9.4-4.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================
 Package               Arch            Version                  Repository                     Size
====================================================================================================
Installing:
 php-pecl-apc          i686            3.1.9-2.el6              CentOS6.3-Repository           96 k
Installing for dependencies:
 php-pear              noarch          1:1.9.4-4.el6            CentOS6.3-Repository          393 k

Transaction Summary
====================================================================================================
Install       2 Package(s)

Total download size: 489 k
Installed size: 2.5 M
Downloading Packages:
Setting up and reading Presto delta metadata
Processing delta metadata
Package(s) data still to download: 489 k
----------------------------------------------------------------------------------------------------
Total                                                               3.3 MB/s | 489 kB     00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : 1:php-pear-1.9.4-4.el6.noarch                                                    1/2
  Installing : php-pecl-apc-3.1.9-2.el6.i686                                                    2/2
  Verifying  : 1:php-pear-1.9.4-4.el6.noarch                                                    1/2
  Verifying  : php-pecl-apc-3.1.9-2.el6.i686                                                    2/2

Installed:
  php-pecl-apc.i686 0:3.1.9-2.el6

Dependency Installed:
  php-pear.noarch 1:1.9.4-4.el6

Complete!

2. Specify shared memory :

[root@centos63 ~]# vi /etc/php.d/apc.ini

On Line 12, specify shared memory size :

; The size of each shared memory segment, with M/G suffix
apc.shm_size=512M
; A "hint" about the number of distinct source files that will be included or
; requested on your web server. Set to zero or omit if you are not sure;

3. Restart Apache :

[root@centos63 ~]# /etc/rc.d/init.d/httpd restart
Stopping httpd:                                            [  OK  ]
Starting httpd:                                            [  OK  ]

4. Create “phpinfo” and please make sure APC has been enabled :

[root@centos63 ~]# vi /var/www/html/phpinfo.php
<?php
phpinfo();
?>

APC

How to Install Wireshark on CentOS 6.3

Wireshark is a free and open-source network packet analyzer that will help to capture network packets and tries to display that packet data as detailed as possible. This post will covers the quick step to install wireshark on linux CentOS 6.3.

[root@centos63 ~]# yum install wireshark -y
[root@centos63 ~]# yum install wireshark -y
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
 * base: mirrors.hostemo.com
 * extras: mirrors.hostemo.com
 * updates: mirrors.hostemo.com
CentOS6.3-Repository                                                         | 4.0 kB     00:00 ...
base                                                                         | 3.7 kB     00:00
extras                                                                       | 3.0 kB     00:00
updates                                                                      | 3.5 kB     00:00
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package wireshark.i686 0:1.2.15-2.el6_2.1 will be installed
--> Processing Dependency: libsmi.so.2 for package: wireshark-1.2.15-2.el6_2.1.i686
--> Processing Dependency: libpcap.so.1 for package: wireshark-1.2.15-2.el6_2.1.i686
--> Processing Dependency: libgnutls.so.26(GNUTLS_1_4) for package: wireshark-1.2.15-2.el6_2.1.i686
--> Processing Dependency: libgnutls.so.26 for package: wireshark-1.2.15-2.el6_2.1.i686
--> Running transaction check
---> Package gnutls.i686 0:2.8.5-4.el6_2.2 will be installed
--> Processing Dependency: libtasn1.so.3(LIBTASN1_0_3) for package: gnutls-2.8.5-4.el6_2.2.i686
--> Processing Dependency: libtasn1.so.3 for package: gnutls-2.8.5-4.el6_2.2.i686
---> Package libpcap.i686 14:1.0.0-6.20091201git117cb5.el6 will be installed
---> Package libsmi.i686 0:0.4.8-4.el6 will be installed
--> Running transaction check
---> Package libtasn1.i686 0:2.3-3.el6_2.1 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================
 Package         Arch       Version                                Repository                  Size
====================================================================================================
Installing:
 wireshark       i686       1.2.15-2.el6_2.1                       CentOS6.3-Repository       9.9 M
Installing for dependencies:
 gnutls          i686       2.8.5-4.el6_2.2                        CentOS6.3-Repository       336 k
 libpcap         i686       14:1.0.0-6.20091201git117cb5.el6       CentOS6.3-Repository       125 k
 libsmi          i686       0.4.8-4.el6                            CentOS6.3-Repository       2.4 M
 libtasn1        i686       2.3-3.el6_2.1                          CentOS6.3-Repository       239 k

Transaction Summary
====================================================================================================
Install       5 Package(s)

Total download size: 13 M
Installed size: 64 M
Downloading Packages:
Setting up and reading Presto delta metadata
Processing delta metadata
Package(s) data still to download: 13 M
----------------------------------------------------------------------------------------------------
Total                                                                12 MB/s |  13 MB     00:01
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : libtasn1-2.3-3.el6_2.1.i686                                                      1/5
  Installing : gnutls-2.8.5-4.el6_2.2.i686                                                      2/5
  Installing : libsmi-0.4.8-4.el6.i686                                                          3/5
  Installing : 14:libpcap-1.0.0-6.20091201git117cb5.el6.i686                                    4/5
  Installing : wireshark-1.2.15-2.el6_2.1.i686                                                  5/5
  Verifying  : 14:libpcap-1.0.0-6.20091201git117cb5.el6.i686                                    1/5
  Verifying  : libsmi-0.4.8-4.el6.i686                                                          2/5
  Verifying  : gnutls-2.8.5-4.el6_2.2.i686                                                      3/5
  Verifying  : libtasn1-2.3-3.el6_2.1.i686                                                      4/5
  Verifying  : wireshark-1.2.15-2.el6_2.1.i686                                                  5/5

Installed:
  wireshark.i686 0:1.2.15-2.el6_2.1

Dependency Installed:
  gnutls.i686 0:2.8.5-4.el6_2.2            libpcap.i686 14:1.0.0-6.20091201git117cb5.el6
  libsmi.i686 0:0.4.8-4.el6                libtasn1.i686 0:2.3-3.el6_2.1

Complete!

How to Setup WordPress Blog on CentOS 6.3

WordPress is an open-source blogging platform. It’s a free blogging tool and content management system (CMS) based on PHP and MySQL. This steps covers how to install the WordPress on linux CentOS 6.3. This post assumed that PHP, apache and MySQL server has been setup properly.

1. Login as a root, go to document’ root folder and download latest wordpress file :

[root@centos63 ~]# cd /var/www/html/
[root@centos63 html]# wget http://wordpress.org/latest.tar.gz

2. Extract the lates.tar.gz files to current directory :

[root@centos63 html]# tar xvzf latest.tar.gz

3. Now create wordpress database. Login to your mySQL database :

[root@centos63 ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.1.61 Source distribution

Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

4. Create Database name “wordpressdb” :

mysql> CREATE DATABASE wordpressdb;
Query OK, 1 row affected (0.08 sec)

5. Create user “wordpressuser” with password “wordpresspassword” :

mysql> CREATE USER 'wordpressuser'@'localhost' IDENTIFIED BY 'wordpresspassword';
Query OK, 0 rows affected (0.06 sec)

6. Grant all privileges to “wordpressdb” to user ” wordpressuser” from localhost access :

mysql> GRANT ALL PRIVILEGES ON wordpressdb.* to wordpressuser@localhost;
Query OK, 0 rows affected (0.04 sec)

7. Check and verify the granted access for user “wordpressuser” :

mysql> SHOW GRANTS FOR 'wordpressuser'@'localhost';
+----------------------------------------------------------------------------------------------------------------------+
| Grants for wordpressuser@localhost                                                                                   |
+----------------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'wordpressuser'@'localhost' IDENTIFIED BY PASSWORD '*E62D3F829F44A91CC231C76347712772B3B9DABC' |
| GRANT ALL PRIVILEGES ON `wordpressdb`.* TO 'wordpressuser'@'localhost'                                               |
+----------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.08 sec)

mysql>

8. For higher security, make wordpress folder readable only from browser :

[root@centos63 ~]# chmod 755 /var/www/html/wordpress

9. Go to your web server terminal or ssh to web server. Copy and rename wp-config-sample.php to wp-config.php:

[root@centos63 ~]# cp /var/www/html/wordpress/wp-config-sample.php /var/www/html/wordpress/wp-config.php

10. Modify the wp-config.php :

[root@centos63 ~]# vi /var/www/html/blog/wp-config.php

Change below database details such as database’ name, database’ username, database’ password nand database’ hostname.

// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
define('DB_NAME', 'wordpressdb');

/** MySQL database username */
define('DB_USER', 'wordpressuser');

/** MySQL database password */
define('DB_PASSWORD', 'wordpresspassword');

/** MySQL hostname */
define('DB_HOST', 'localhost');

11. To configure wordpress, navigate the browser to http://servername/wordpress/. Please complete the form Click “Install WordPress”

Site Title : Blog Title
Username : Prefered username
Password, twice : Your password
Your E-mail : Your Email

wordpress

12. To login, navigate the browser to http://servername/wordpress/wp-login.php :
wordpress