What is NTP?

NTP is stand for Network Time Protocol. It is used for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. NTP uses UDP on port 123 as its transport layer.

Keeping the date/time synchronized throughout all computers / servers is really necessary. Solaris already comes with the ntp daemon, called "xntpd".

• Check whether NTP daemon is already running / not

root@server:~# svcs -a | grep ntp
disabled       May_11   svc:/network/ntp:default

JasperServer (JS) builds on JasperReports (JR) as a comprehensive family of Business Intelligence (BI) products, providing robust static and interactive reporting, report server, and data analysis capabilities. For business intelligence users, Jaspersoft offers JasperAnalysis, which runs seamlessly on JasperServer.

Note: This blog is updated based on JS-3.5 GA release
Last updated: 2009-05-08 16.00 GMT+8

What's New in JasperServer 3.5

JasperServer now includes these features:

• Upgrade Mondrian to 3.0
• Dimension sharing within a cube
• Support for dozens of new scalar functions in MDX
• New JasperAnalysis UI
• Improved look and feel as well as an improved tool bar within analysis views.
• Encrypt JDBC password
• Export/Import now supports encryption of JDBC passwords

1. How to unmount the unresponsive media drive

First, simulate it. Stick a disk in your CD/DVD drive, open up a terminal, and mount the CD/DVD drive.
If your system automatically mount, then you can skip the mounting part.

root@server:~# mount /media/cdrom
root@server:~# cd /media/cdrom
root@server:~# while [ 1 ]; do echo "All your drives are belong to us!"; sleep 30; done

This documents updated for JasperServer version 3.0.0

What is JasperServer

JasperServer is an open source business intelligence suite, built by the developers of JasperReports. It providing common services like security and metadata management, and the capability to easily add additional functionality.It also provides a Web and Web services based environment for reporting, data analysis (OLAP), and data integration.

What is JasperReports

JasperReports is a powerful open source Java reporting tool that has the ability to deliver rich content onto the screen, to the printer or into PDF, HTML, XLS, CSV and XML files. It is entirely written in Java and can be used in a variety of Java enabled applications, including J2EE or Web applications, to generate dynamic content. Its main purpose is to help creating page oriented, ready to print documents in a simple and flexible manner.

SSH Tunneling is also known as Port Forwarding is a way to forward insecure TCP traffic through SSH Secure Shell. For an example, we can make a secure POP3 access by forwarding non-standard local port to remote POP3 port using SSH.

ssh -f user@mail-server -L 2000:localhost:110 -N

-f -> Requests ssh to go to background just before command execution
-N -> Do not execute a remote command. This is useful for just forwarding ports.
-N port:host:hostport -> Specifies that the given port on the local (client) host is to be forwarded to the given host and port on the remote side.

PostgreSQL is an object-relational database developed on the Internet by a group of developers spread across the globe. It is an open-source alternative to commercial databases like Oracle and Informix. PostgreSQL was originally developed at the University of California, Berkeley. In 1996, a group began development of the database on the Internet. They used e-mail to share ideas and file servers to share code. PostgreSQL is now comparable to proprietary databases in terms of features, performance and reliability. It has transactions, views, stored procedures and referential integrity constraints. It supports a large number of programming interfaces, including ODBC, Java (JDBC), Tcl/Tk, PHP, Perl and Python. PostgreSQL continues to improve at a tremendous pace thanks to a talented pool of internet developers.

What is DHCP?

Dynamic Host Configuration Protocol (DHCP) is network protocol for automatically assigning TCP/IP information to client machines. Each DHCP client connects to the centrally-located DHCP server which returns that client's network configuration including IP address, gateway, host name, and DNS servers.

Why do we need DHCP server?

DHCP is useful for fast delivery of client network configuration. When configuring the client system, the administrator can choose DHCP and not have to enter an IP address, netmask, gateway, or DNS servers. The client retrieves this information from the DHCP server. DHCP is also useful if an administrator wants to change the IP addresses of a large number of systems. Instead of reconfiguring all the systems, he can just edit one DHCP configuration file on the server for the new set of IP address. If the DNS servers for an organization changes, the changes are made on the DHCP server, not on the DHCP clients. Once the network is restarted on the clients (or the clients are rebooted), the changes will take effect.

I have been searching for a full-featured and platform independent HylaFAX client and finally i found YajHFC (Yet another Java HylaFAX Client). This application is written completely in Java, therefore it can be use for both Linux and Windows environment. YajHFC has the following features:

• Faxing documents in PostScript, PDF, JPEG, PNG and GIF format
• Polling faxes
• Support for generating cover pages from templates
• Viewing sent and received faxes
• Phone book
• Visible table columns may be selected in a dialog
• Runs under Windows, Linux and Mac OS X (and probably other platforms if a suitable JRE is available)
• Supports four languages: English, French, German and Spanish

This is a guide line to install Perle Multimodem Fax board driver (PCI-RAS V.92) on Ubuntu / Debian. For more information about this product, please visit at http://www.perle.com.

Become super user and install build-essential, linux-headers packages

user@server:~# sudo su -
Password:

root@server:~# apt-get install build-essential linux-headers-`uname -r`

What is HylaFAX?

HylaFAX is an enterprise-class system for sending and receiving facsimiles as well as for sending alpha-numeric pages.

The software is designed around a client-server architecture. Fax modems may reside on a single machine on a network and clients can submit an outbound job from any other machine on the network. Client software is designed to be lightweight and easy to port.

HylaFAX is designed to be very robust and reliable. The fax server is designed to guard against unexpected failures in the software, in the configuration, in the hardware and in general use. HylaFAX can support multiple modems and a heavy traffic load.

If you expect to send more than a few facsimiles a day, then HylaFAX is the fax package for you!