SSH Public Key Based Authentication

Task: Generating SSH Keys

First, log on to your workstation ( for example log on to workstation called as vivek user). Please refer the following sample setup – You will be log in, on your local system, AS THE USER you wish to make passwordless ssh connections.


Create the cryptographic Key on FreeBSD / Linux / UNIX workstation, enter:

ssh-keygen -t rsa

Assign the pass phrase (press [enter] key twice if you don’t want a passphrase). It will create 2 files in ~/.ssh directory as follows:

~/.ssh/id_rsa : identification (private) key
~/.ssh/ : public key

Use scp to copy the (public key) to server as authorized_keys2 file, this is know as Installing the public key to server.

scp .ssh/

From FreeBSD workstation login to server:


Changing the pass-phrase on workstation (if needed): Continue reading


Apache,MySQL, PHP and Phpmyadmin on CentOS

Installing MySQL 5

To install MySQL, we do this:

yum -y install mysql mysql-server

Then we create the system startup links for MySQL (so that MySQL starts automatically whenever the system boots) and start the MySQL server:

chkconfig –levels 235 mysqld on
/etc/init.d/mysqld start

Set passwords for the MySQL root account: Continue reading


ধন ধান্য পুষ্প ভরা… আমাদের এই বসুন্ধরা…

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Set date/time permanently on Linux System

First you need to ssh to the server and be root and then do these step by step: Read More


Icinga Installation on Debian Squeeze- Part-3

Adding and Monitoring a Remote Server to Icinga

Monitoring localhost is nice, but of course, it would be even better if we could monitor all of our servers in one location. This is possible with Icinga, and this chapter describes how we can add our second Debian Squeeze server ( to the setup.

To do this, we need to install the Nagios NRPE (Nagios Remote Plugin Executor) server on server2, and the Nagios NRPE plugin on server1. The NRPE server will listen on server2; server1 will connect to it using the NRPE plugin and pass commands to it that the NRPE server will execute on server2; it will pass back the results to server1. Continue reading


Icinga Installation on Debian Squeeze- Part-2

Configuring Icinga

The main Icinga configuration file is /etc/icinga/icinga.cfg, additional configurations are stored in /etc/icinga/commands.cfg and /etc/icinga/resource.cfg. Usually the default configuration is ok, so you don’t have to change these files.

The first thing you should change is the contact details in /etc/icinga/objects/contacts_icinga.cfg so that notifications are sent to the correct email address:

vi /etc/icinga/objects/contacts_icinga.cfg

define contact{
contact_name root
alias Falko Timme
service_notification_period 24×7
host_notification_period 24×7
service_notification_options w,u,c,r
host_notification_options d,r
service_notification_commands notify-service-by-email
host_notification_commands notify-host-by-email
[...] Continue reading


Icinga Installation on Debian Squeeze- Part-1

Icinga is an enterprise grade open source monitoring system which keeps watch over networks and any conceivable network resource, notifies the user of errors and recoveries and generates performance data for reporting. It is a fork of Nagios. This tutorial explains how to install Icinga on a Debian Squeeze server to monitor this server and another Debian Squeeze server.

Before we begin installation, let’s prepare the enviornment first by installing Apache, MySQL, Postfix, and Courier-IMAP/-POP3 and some other packages-

Change The Default Shell

/bin/sh is a symlink to /bin/dash, however we need /bin/bash, not /bin/dash. Therefore we do this: Continue reading


Quality Interior and Exterior!

[caption id="attachment_1560" align="alignleft" width="600"]This backyard beach fire pit This backyard beach fire pit[/caption] [caption id="attachment_1559" align="alignleft" width="600"]This lamp that turns any room into a mysterious forest This lamp that turns any room into a mysterious forest[/caption] Read More


Change Windows RDP default listening port 3389

  1. Start Registry Editor.
  2. Locate and then click the following registry subkey:
  3. On the Edit menu, click Modify, and then click Decimal.
  4. Type the new port number, and then click OK.
  5. Quit Registry Editor.
  6. Restart the computer.

Note When you try to connect to this computer by using the Remote Desktop connection, you must type the new port. Maybe you have to set the firewall to allow the new port number before you connect to this computer by using the Remote Desktop connection. Read More


Yum Cache Clear command

When a package is downloaded, installed and is removed there is a chance that the package may still be saved/stored in the yum’s cache. So to clean all the cached packages from the enabled repository cache directory, login as root and execute the following: Read More

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Hi, I am Hasan T. Emdad Rumi, an IT Project Manager, system administrator,a web developer and IT consultant from Dhaka, Bangladesh. I have prior experience in managing numerous local and international projects- such as Telco VAS & NMC, Virtualization & Cloud Networks, PKI Certifying Authority, Offshore Software Development Team. Worked with Orascom Telecom (Banglalink), Network Elites (US), BTRC, BTT (Turkey).

Current Engagement Country Manager for BTT (Turkey) and Head of Technical Solutions at Mango Teleservices Limited . Please do get in contact with me[h.t.emdad at] and I will be delighted to exchange my views.

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