Sinan Polat


How to install PAE kernel on CentOS

When you have 4GB or more memory and you have a 32-bit kernel running, your machine will be limited to use around 3GB of memory. All you have to do is install PAE kernel package. 1. Install the PAE kernel package: # yum install kernel-PAE 2. Check your grub menu list, the ‘default’ value should […]

IIS: Cannot read configuration file due to insufficient permissions

Normally I don’t work with Windows Servers and/or IIS, but sometimes you don’t have any other option. I couldn’t access the web files, it was displaying an ‘500 – Internal server error‘ error. The more detailed error showed me the following: Cannot read configuration file due to insufficient permissions After Googling, searching, trying and again […]

How to reset the MySQL root password

If you have forgotten the mysql root passwod, you can set a new password if you have root access to the server. 1. Stop MySQL server. # /etc/init.d/mysql stop 2. Start MySQL with –skip-grant-tables option. # mysqld_safe –skip-grant-tables & 3. Connect to MySQL as root. # mysql -u root 4. Set new mysql root password. […]

6 System Monitoring tools for Linux

1. top – Display Linux tasks The top program provides a system summary information as well as a list of tasks currently running. 2. free – Memory usage The free program will display amount of free and used memory in the system. Sample (the option ‘-m’ will show the results in megabytes): # free -m […]

Cannot access Plesk login page

After the installation / upgrade of Plesk you can access the Plesk Control Panel via URL: or https://your-servers-IP:8443 but probably you get redirected to https://incorrect-url:8443/relay This is caused by a misconfiguration of your hostname on your server. You can solve this by running the following command as root: # /usr/share/plesk-billing/update-hostname –new-hostname <Your server IP> […]

Starting Plesk failed after upgrade to Plesk 10.2.0

I have seen a lot of topics about failing Plesk to start after upgrading to 10.2.0. I have got the same problem, the error message was: Restarting SWsoft control panels server…Duplicate config variable in conditional 1 global/SERVERsocket==:8443: fastcgi.server 2011-04-17 17:44:02: (configfile.c.838) source: /usr/share/sw-cp-server/ line: 103 pos: 14 parser failed somehow near here: (EOL) 2011-04-17 17:44:02: […]

How to block IP and Ports with IPtables

How to block IP and/or Ports with IPtables under Linux? Blocking an incoming port First you have to know the port number which you want to block, for a list of port numbers you can use /etc/services as a reference. The syntax is as follow (make sure you are root or have root privileges): # […]

Upgrading Debian (Lenny) to Debian Squeeze

Debian Squeeze (stable) was released on February 6, 2011. 1. First update all packages which are currently installed # apt-get update # apt-get upgrade 2. Open /etc/apt/sources.list and replace all occurrences of lenny with squeeze 3. Update the apt repository # apt-get update 4. Upgrade apt, dpkg and aptitude #¬†apt-get install apt dpkg aptitude 5. […]

Upgrading CentOS to CentOS 5.6

CentOS 5.6 has been released on April 8th, 2011. If you are running CentOS 5.5 you can simply upgrade to CentOS 5.6 via yum by running: # yum update If upgrading from a version earlier than CentOS 5.5, it is advised to follow this procedure: # yum clean all # yum update glibc\* # yum […]

Installing / Enabling SpamAssassin on DirectAdmin

By default SpamAssassin is not enabled nor installed on a system with DirectAdmin. I wrote a very simple How-To to install SpamAssassin. Install SpamAssassin: # cd /usr/local/directadmin/scripts # ./ Probably you will get some Perl error like: REQUIRED module out of date: Archive::Tar optional module missing: Digest::SHA optional module missing: Mail::SPF optional module missing: IP::Country […]