Spamassassin - #1 Open-Source Spam Filter

SpamAssassin is a e-mail spam filtering based on content-matching rules.

SpamAssassin uses a variety of spam-detection techniques, that includes DNS-based and fuzzy-checksum-based spam detection, Bayesian filtering, external programs, blacklists and online databases.

The program can be integrated with the mail server to automatically filter all mail for a site. It can also be run by individual users on their own mailbox and integrates with several mail programs.SpamAssassin is highly
configurable.

If used as a system-wide filter it can still be configured to support per-user preferences.

Home Page: http://spamassassin.apache.org/
For binary package and other information: http://pkgs.org/search/?keyword=SpamAssassin


Thanks to Dhanasekar, ILUGC

Sentinella - System Monitoring Services

While monitoring the CPU, memory, hard drive and network usage, Sentinella can be programmed to take specific actions when set-points for utilization or time are met.

It can power off, reboot or hibernate your system, kill an active process, throw an alarm or execute any command.

It can measure the following conditions:
- CPU load
- Memory used
- Network traffic
- Date and time
- The existence of a process

And the possible actions are:
- Shutdown/Reboot the computer
- Standby/Suspend/Hibernate
- Execute a command
- Play an alarm
- Kill a process

Version: Sentinella 0.9.0-3
Size: 59.3 MB to download, 192.2 MB when installed

For more details: http://sentinella.sourceforge.net/

Thanks to : Dhanasekar, ILUG, Chennai

Munin - Networked Resource Monitoring Tool

Munin is a networked resource monitoring tool that can help analyze resource trends and "what just happened to kill our performance?" problems. It is designed to be very plug and play. A default installation provides a lot of graphs with almost no work.

Munin is a highly flexible and powerful solution used to create graphs of virtually everything imaginable throughout your network, while still maintaining a rattling ease of installation and
configuration.

This package contains the grapher/gatherer. You will only need one instance of it in your network. It will periodically poll all the nodes in your network it's aware of for data, which it in turn will use to create graphs and HTML pages, suitable for viewing with your graphical web browser of choice.

It is also able to alert you if any value is outside of a preset boundary, useful if you want to be alerted if a filesystem is about to grow full, for instance. You can do this by making Munin run an arbitrary command when you need to be alert it, or make use of the intrinsic Nagios support.

Munin is written in Perl, and relies heavily on Tobi Oetiker's excellent RRDtool.

Version: munin 1.4.6-3ubuntu3.1
Size: 8.5 MB to download, 25.2 MB when installed

For more details: http://munin-monitoring.org/

Thanks : Dhanasekar, ILUGC

OProfile - Performance Profiling Tool

OProfile is a performance profiling tool for Linux systems, capable of profiling all running code at low overhead. It consists of a daemon for collecting sample data, plus several post-profiling tools for
turning data into information.

OProfile leverages the hardware performance counters of the CPU to enable profiling of a wide variety of interesting statistics, which can also be used for basic time-spent profiling. All code is profiled:
hardware and software interrupt handlers, kernel modules, the kernel, shared libraries, and applications (the only exception being the OProfile interrupt handler itself). Note that different architectures can use different hardware mechanisms to collect data.

Version: OProfile 0.9.8

For more details: http://oprofile.sourceforge.net/news/


Thanks : Dhanasekar, ILUGC

GIP - IP Address Calculator

GIP is an application for making IP address based calculations. For example, it can display IP addresses in binary format. We can also calculate subnet addresses using GIP.

Gip provides system administrators with tools for IP address based calculations.
For example, an administrator who needs to find out which IP prefix length equals the IP netmask 255.255.240.0, just types in the mask and gets  the prefix length presented.But

Also many advanced calculations can be made. Gip can convert an address range into a list of prefix lengths. It can also splits subnets using a given IP netmask or IP prefix length.

Current Version:  GIP 1.7.0-1-3
Size: 1.2 MB to download, 5.7 MB when installed

For more details: http://code.google.com/p/gip/


- Thanks to Dhansekar, ILUGC.