Five open source technologies for 2012

Posted by Unknown Rabu, 04 Januari 2012 0 komentar

Next year, if all goes according to plan, Red Hat will become the first open source software company to generate more than US$1 billion a year in revenue. It will be a watershed moment for the open source community, who have long seen their approach of community-based development as a viable, even superior, alternative to traditional notions of how software should be written.
"I think we're seeing a fundamental shift in where innovation happens, going from the labs of a few software companies to these massive open source efforts," said Jim Whitehurst, president and CEO of Red Hat.
Certainly, open source has left the proprietary software world in turmoil over the past few years, as Linux, the Apache Web server, Perl, Apache, Hadoop, OpenOffice, GIMP and dozens of other programs put the pinch on their commercial counterparts. But what are tomorrow's open source heavy hitters? Here are five projects to watch closely in 2012. They may form the basis for new businesses and new industries. Or they may just capture the minds of developers and administrators with some easier, or at least less expensive, way of getting the job done.

--Nginx
For the better part of the last decade, the choice for Web server software has been pretty stable. Apache has been used on the majority of Web servers while Microsoft's IIS (Internet Information Services) is used across many of the rest. Over the past few years, however, use of a third entrant, Nginx (pronounced "engine-x"), has been on the rise, thanks to the software's ability to easily handle high-volume traffic.
Nginx is already run on 50 million different Internet domains, or about 10 percent of the entire Internet, the developers of the software estimate. It is particularly widely used on highly trafficked Web sites, such as Facebook, Zappos, Groupon, Hulu, Dropbox, and WordPress. Not surprisingly, the software's creator, Igor Sysoev, designed Nginx in 2004 specifically to handle a large numbers of concurrent users -- up to 10,000 connections per server. "It is a very lean architecture," said Andrew Alexeev, a co-founder of a company that offers a commercial version of the software, called Nginx.
The upcoming year promises to be a good one for Nginx. Last year, Nginx got $3 million in backing from a number of venture capital firms, including one supported by Dell CEO Michael Dell. It partnered with Jet-Stream to provide Nginx for that software vendor's CDN (content delivery network) package. It also is working with Amazon to streamline Nginx for the AWS (Amazon Web Service) cloud service.
Beyond Nginx's use in large Web operations, Alexeev sees wider use for Nginx in the emerging cloud computing and shared services market. "This is where we can add the most benefit," Alexeev said. The next major release of the software, due next year, will be more pliable for shared hosting environments. It will be better able to handle DDoS (Distributed Denial of Service Attacks), and come with additional security features, he said.

--OpenStack
The OpenStack project arrived relatively late to the cloud computing party, but it comes with one particularly indispensable feature: scalability.
"We're not talking about [using OpenStack to run a] cloud of 100 servers or even 1,000 servers, but tens of thousands of servers. Other options out there aren't really considering that scale," said Jonathan Bryce, chairman of the OpenStack Project Policy Board.
Since its launch in July 2010, OpenStack quickly gained a great deal of support from IT firms interested in the cloud computing space, such as Hewlett-Packard, Intel and Dell. OpenStack devotees like to call their work the fastest growing open source project, with involvement from over 144 companies and 2,100 participants. Dell launched a package, called the Dell OpenStack Cloud Solution, which combines OpenStack with the company's own servers and software. HP launched a beta public cloud service with the technology as well.
The core computational components of OpenStack were developed at NASA Ames Research Center, for an internal cloud to store large amounts of space imagery. Originally, the NASA administrators tried using the Eucalyptus software project platform, but found challenges in scaling the software to the required levels, according to Chris Kemp, who oversaw the development of the OpenStack cloud controller when he was CIO of NASA Ames.
To aid in wider adoption, OpenStack is being outfitted with a number of new features that should make it more palatable for enterprises, said John Engates, chief technology officer for managed hosting provider Rackspace. One project, called Keystone, will allow organizations to integrate OpenStack with their identity management systems, those based on Microsoft Active Directory or other LDAP (Lightweight Directory Access Protocol) implementations. Also, developers are working on a front-end portal for the software as well. Rackspace, which first partnered with NASA to package OpenStack for general usage, is also spinning off the project as a fully independent stand-alone entity, in hopes that it will be an attractive option for more cloud providers.
"2011 was the year for building the base of the product, but I think 2012 is where we really start to use that base for a lot of private and public clouds," Engates said.

--Stig
The past year has seen the dramatic growth in the use of nonrelational databases, such as Cassandra, MongoDB, CouchDB and countless others. But at the NoSQL Now conference, held last September, much of the buzz surrounded a still unreleased data store called Stig. With any luck, we will see Stig in 2012.
Stig is designed for the unique workloads of social networking sites, its maintainers claim. It was created at the social networking site Tagged by software engineer Jason Lucas, who calls the technology a distributed graph database. It is designed to support heavily interactive and social Web applications. The data store's architecture allows for inferential searching, allowing users and applications to look for connections between disparate pieces of information. Because it was written, in part, in the Haskell functional programming language, it can easily divide up its workload across multiple servers.
Stig is still a bit of a mystery, as it hasn't been actually released yet. But observers are predicting it could fit a niche in the social networks and other applications that keep a wide range of data. The needs of social networking services are inherently different from other types of jobs, and would benefit from a database attuned to its needs, Lucas explained. "You can't be a relevant service in this space without being able to scale to a planetary size," he said.
Stig is currently operating on one server at Tagged, though the company expects to expand its use to the point where it will be the sole database for the company. Originally, the developers were planning to source code by December, but moved back the release to sometime in 2012.
"What I did see looked very interesting," said Dan McCreary, a semantic solutions architect for the Kelly-McCreary & Associates consulting firm. He praised the database's functional language architecture, which should ease the deployment of the database across multiple servers.
--Linux Mint
Despite years of advocacy on the part of open source adherents, Linux has never had a strong presence on the desktop. But usually there is always one user-friendly Linux distribution to use, as an alternative to Microsoft Windows. In recent years, Canonical's Ubuntu has fulfilled this role, though the increasingly popular Linux Mint may trump Ubuntu by being even easier to use.
Software engineer Clement Lefebvre first crafted Linux Mint after a gig of reviewing other Linux distributions for various online forums. From this work, Lefebvre developed ideas about what features should be in the ideal distribution. Just as Canonical appropriated the Debian Linux distribution for its own massively popular Ubuntu, Lefebvre used Ubuntu as the base for Linux Mint. Today, the Linux Mint project is funded by donations, advertising revenue from its Web site, and income derived from user searches, the last through a controversial partnership with DuckDuckGo.
Linux Mint is designed specifically for people who just want a desktop OS, and who don't wish to learn more about how Linux works (i.e. non-Linux hobbyists). This approach makes installing and running the software easy and maintenance pretty much a nonissue. Even more than Ubuntu, Mint emphasizes easy usability, at the expense of not using new features until they have proven themselves trustworthy.
For instance, Mint eschews the somewhat controversial Unity desktop interface, which Canonical adopted to more easily port Ubuntu to mobile platforms. Instead, Mint sticks with the more widely known, and more mature, Gnome interface.
Such rigorous adherence to usability may be helping Linux Mint, much to the detriment of Ubuntu, in fact. The Linux Mint project claims its OS is now the fourth most widely used desktop OS in the world, after Windows, Apple Mac and Ubuntu. Over the past year, Mint has even usurped Ubuntu as the distribution that generates the most page views on the DistroWatch Linux news site, a metric generally thought to reflect the popularity of Linux distributions. No doubt 2012 will see only more growth for the OS.

--Gluster
Could Red Hat revolutionize the world of storage software in much the same way it revolutionized the market for Unix-based OSes? In October, Red Hat purchased Gluster, which, with its GlusterFS file system, makes open source software that clusters commodity SATA (Serial Advanced Technology Attachment) drives and NAS (network attached storage) systems into massively scalable pools of storage. Red Hat plans to apply the method it used to dominate the market for Linux OSes for the storage space as well.
According to Red Hat's Whitehurst, the storage software market generates $4 billion in revenue annually, though that's not why the company was interested in the technology. Instead, Red Hat was interested in finding a storage technology that would make cloud migrations easier. "We look for places where open source would be particularly powerful as a way to innovate, and we look for areas in the stack where we think we can monetize," he said. "There are not other solutions like that out there."
The software has some momentum, at least in terms of administrators downloading and testing the software. Over the past year, GlusterFS downloads increased by 300 percent. In November, the software was downloaded over 37,000 times.

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30 Best Sources For Linux / *BSD / Unix Documentation On the Web

Posted by Unknown 0 komentar

Man pages are written by sys-admin and developers for IT techs, and are intended more as a reference than as a how to. Man pages are very useful for people who are already familiar with Linux, Unix, and BSD operating systems. Use man pages when you just need to know the syntax for particular commands or configuration file, but they are not helpful for new Linux users. Man pages are not good for learning something new for the first time. Here are thirty best documentation sites on the web for learning Linux and Unix like operating systems.
Dennis Ritchie and Ken Thompson working with UNIX PDP11
This article is dedicated to the memory of Dennis Ritchie (1941-2011).

Please note that BSD manpages are usually better as compare to Linux.

#1: Red Hat Enterprise Linux


Red hat Enterprise Linux Docs
RHEL Docs

RHEL is developed by Red Hat and targeted toward the commercial market. It has one of the best documentations covering basis of RHEL to advanced topics like security, SELinux, virtualization, directory server, clustering, JBOSS, HPC, and much more. Red Hat documentation has been translated into twenty-two languages and is available in multi-page HTML, single-page HTML, PDF, and EPUB formats. The good news is you can use the same documentation for CentOS or Scientific Linux (community enterprise distros). All of these documents ship with the OS, so if you don't have a network connection, then you have them there as well. The RHEL docs covers everything from installation to configuring clusters. The only downside is you need to be a paid customer. This is perfect for an enterprise company.
  1. RHEL Documentation: Unknown format
  2. Support forums: Only available to Red Hat customer portal to submit a support case.

A Note About CentOS Wiki and Forums


Centos Linux Wiki
Centos Linux Wiki

CentOS (Community ENTerprise Operating System) is a free rebuild of source packages freely available from a RHEL. It provides truly reliable, free enterprise Linux for personal and other usage. You will get RHEL stability without the cost of certification and support. CentOS wiki divided into Howtos, Tips & Tricks, and much more at the following locations:
  1. Documentation Wiki
  2. Support forum

#2: Arch Wiki and Forums


Arch Linux wiki and tutorials
Arch Linux wiki

Arch Linux is an independently developed, Linux operating system and it comes with pretty good documentation in form of wiki based site. It is developed collaboratively by a community of Arch users, allowing any user to add and edit content. The articles are divided into various categories like networking, optimization, package management, system administration, X window system, and getting & installing Arch Linux. The official forums are useful for solving many issues. It has total 40k+ registered users with over 1 million posts. The wiki contains some general information that can also apply in other Linux distros.
  1. Arch community Documentation: Wiki format
  2. Support forums: Yes

#3: Gentoo Linux Wiki and Forums


Gentoo Linux Handbook and Wiki
Gentoo Linux Wiki

Gentoo Linux is based on the Portage package management system. The Gentoo user compiles the source code locally according to their chosen configuration. The majority of users have configurations and sets of installed programs which are unique to themselves. The Gentoo give you some explanation about the Gentoo Linux and answer most of your questions regarding installations, packages, networking, and much more. Gentoo has very helpful forumwith over one hundred thirty-four thousand plus users who have posted a total of 5442416 articles.
  1. Gentoo community documentation: Handbook and Wiki format
  2. Support forums: Yes
  3. User-supplied documentation available at gentoo-wiki.com

#4: Ubuntu Wiki and Documentation

Ubuntu is one of the leading desktop and laptop distro. The official documentation developed and maintained by the Ubuntu Documentation Project. You can access a wealth of information including a getting started Guide. The best part is information contained herein may also work with other Debian-based systems. You will also find the community documentation for Ubuntu created by its users. This is a reference for Ubuntu-related 'Howtos, Tips, Tricks, and Hacks'. Ubuntu Linux has one of the biggest Linux communities on the web. It offers help to the both new and experienced users.
Ubuntu Linux Wiki and Forums
Ubuntu Linux Wiki

  1. Ubuntu community documentation: wiki format.
  2. Ubuntu official documentation: wiki format.
  3. Support forums: Yes.

#5: IBM Developer Works

IBM developer works offers technical resources for Linux programmers and system administrators. It contains hundreds of articles, tutorials, and tips to help developers with Linux programming and application development, as well as Linux system administration.
IBM: Technical for Linux programmers and system administrators
IBM developerworks

  1. IBM Developer Works Documentation: Unknown format
  2. Support forums: Yes.

#6: FreeBSD Documentation and Handbook

The FreeBSD handbook is created by the FreeBSD Documentation Project. It describes the installation, administration and day-to-day use of the FreeBSD OS. BSD manpages are usually better as compare to GNU/Linux man pages. The FreeBSD comes with all the documents with upto date man pages. The FreeBSD Handbook covers everything. The handbook contains some general Unix information that can also apply in other Linux distros. The official FreeBSD forums also provides helps whenever you will get stuck with problems.
Freebsd Documentation
Freebsd docs

  1. FreeBSD Documentation: Unknown format
  2. Support forums: Yes.

#7: Bash Hackers Wiki


Bash hackers wiki for bash users
Bash hackers wiki

This is an excellent resource for bash user. The bash hackers wiki is intended to hold documentations of any kind about the GNU Bash. The main motivation was to provide human-readable documentation and information to not force users to read every bit of the Bash manpage - which is hard sometimes. The wiki is divided into various sections such as - scripting and general information, howtos, coding style, bash syntax, and much more.
  1. Bash hackers wiki in wiki format

#8: Bash FAQ


Bash FAQ: Answers to frequently asked questions about GNU/BASH
Bash FAQ

A wiki designed for new bash users. It has good collections to frequently asked questions on channel #bash on the freenode IRC network. These answers are contributed by the regular members of the channel. Don't forget to check out common mistakes made by Bash programmers, in BashPitfalls section. The answers given in this FAQ may be slanted toward Bash, or they may be slanted toward the lowest common denominator Bourne shell, depending on who wrote the answer. In most cases, an effort is made to provide both a portable (Bourne) and an efficient (Bash, where appropriate) answer.
  1. Bash FAQ in wiki format.

#9: Howtoforge - Linux Tutorials


Howtoforge
Howtoforge

Fellow blogger Falko has some great stuff over at How-To Forge. The site provides Linux tutorials about various topic including its famous "The Perfect Server" series. The site is divided into various topics such as web-server, Linux distros, DNS servers, Virtualization, High-availability, Email and anti-spam, FTP servers, programming topics, and much more. The site is also available in German language.
  1. Howtoforge in html format.
  2. Support forums: Yes

#10: OpenBSD FAQ and Documentation


OpenBSD Documenation
OpenBSD Documenation

OpenBSD is another Unix-like computer operating system based on Berkeley Software Distribution (BSD). It was forked from NetBSD by project. The OpenBSD is well known for the quality code, documentation, uncompromising position on software licensing, with strong focus on security. The documenation is divided into various topics such as - installations, package management, firewall setup, user management, networking, disk / RAID management and much more.
  1. OpenBSD in html format.
  2. Support forums: No, but mail lists are available.

#11: Calomel - Open Source Research and Reference

This amazing site dedicated to documenting open source software, and programs with special focus on OpenBSD. This is one of the cleanest and easy to to navigate website, with focus on the quality content. The site is divided into various server topic such as DNS, OpeBSD, security, web-server, Samba file server, various tools, and much more.
Open Source Research and Reference Documentation
Open Source Research and Reference Documentation

  1. Calomel Org in html format.
  2. Support forums: No

#12: Slackware Book Project


Slackware Linux Book and Documentation
Slackware Book

Slackware Linux was my first distro. It was one of the earliest distro based on the Linux kernel and is the oldest currently being maintained. The distro is targeted towards power users with strong focus on stability. Slackware is one of few the most "Unix-like" Linux distribution. The official slackware book is designed to get you started with the Slackware Linux operating system. It's not meant to cover every single aspect of the distribution, but rather to show what it is capable of and give you a basic working knowledge of the system. The book is divided into various topics such as Installation, Network & System Configuration, System administration, Package management, and much more.
  1. Slackware Linux books in html, pdf, and other format.
  2. Support forums: Yes

#13: The Linux Documentation Project (TLDP)


Linux Learning Site and Documentation
TLDP

The Linux Documentation Project is working towards developing free, high quality documentation for the Linux operating system. The site is created and maintained by volunteers. The site is divided into subject-specific help, longer and in-depth guide books, and much more. I recommend this document which is both a tutorial and a reference on shell scripting with Bash. The single list of HOWTOs is also a good starting point for new users.
  1. The Linux documentation project available in multiple formats.
  2. Support forums: No

#14: Linux Home Networking


Linux Home Networking
Linux Home Networking

Linux home networking is another good resource for learning Linux. This site covers topics needed for Linux software certification exams, such as the RHCE, and many computer training courses. The site is divided into various topics such as networking, samba file server, wirless networking, web-server, and much more.
  1. Linux home networking available in html and PDF (with small fee) formats.
  2. Support forums: Yes

#15: Linux Action Show


Linux Podcast
Linux Podcast From LAS

Linux Action Show ("LAS") is a podcast about Linux. The show is hosted by Bryan Lunduke, Allan Jude, and Chris Fisher. It covers the latest news in the FOSS world. The show reviews various apps and Linux distros. Sometime an interview with a major personal in the open source world is posted on the show.
  1. Linux action show available in audio/video format.
  2. Support forums: Yes

#16: Commandlinefu

Commandlinefu lists various shell commands that you may find interesting and useful. All commands can be commented on, discussed and voted up or down. Ths is an awesome resource for all Unix command line users. Don't forget to checkout all top voted commands here.
The best Unix / Linux Commands By Commandlinefu
Commnandlinefu

  1. Commandlinefu available in html format.
  2. Support forums: No

#17: Debian Administration Tips and Resources

This site covers topics, tips, and tutorial only related to Debian GNU/Linux. It contain interesting and useful information related to the System Administration. You can contribute an article, tip, or question here. Don't forget to checkout top articles posted in the hall of fame section.
Debian Linux Adminstration: Tips and Tutorial For Sys Admin
Debian Linux Adminstration: Tips and Tutorial For Sys Admin

  1. Debian administration available in html format.
  2. Support forums: No

#18: Catonmat - Sed, Awk, Perl Tutorials


Sed, Awk, Perl Tutorials
Catonmat

This site run by a fellow blogger Peteris Krumins. The main focus is on command line and Unix programming topics such as sed, perl, awk, and others. Don't forget to check out introduction to sed, sed one liner explained, the definitive guide to Bash Command line history, and awk liner explained.
  1. catonmat available in html format.
  2. Support forums: No

#19: Debian GNU/Linux Documentation and Wiki


Debian Linux Tutorials and Wiki
Debian Linux Wiki

Debian is another Linux based operating system that primarily uses software released under the GNU General Public. Debian is well known for strict adherence to the philosophies of Unix and free software. It is also one of popular and influential Linux distribution. It is also used as a base for many other distributions such as Ubuntu and others. The Debian project provides its users with proper documentation in an easily accessible form. The site is divided into wiki, installation guide, faqs, and support forum.
  1. Debian GNU/Linux documentation available in html and other format.
  2. Debian GNU/Linux wiki
  3. Support forums: Yes

#20: Linux Sea

The book "Linux Sea" offers a gentle yet technical (from end-user perspective) introduction to the Linux operating system, using Gentoo Linux as the example Linux distribution. It does not nor will it ever talk about the history of the Linux kernel or Linux distributions or dive into details that are less interesting for Linux users.
  1. Linux sea available in html format.
  2. Support forums: No

#21: Oreilly Commons


Oreilly Free Linux / Unix / Php / Javascript / Ubuntu Books
Oreilly books

The oreilly publishing house has posted quite a few titles in wiki format for all. The purpose of this site is to provide content to communities that would like to create, reference, use, modify, update and revise material from O'Reilly or other sources. The site includes books about Ubuntu, Php, Spamassassin, Linux, and much more all for free.
  1. Oreilly commons available in wiki format.
  2. Support forums: No

#22: Ubuntu Pocket Guide


Ubuntu Book For New Users
Ubuntu book

This book is written by Keir Thomas. This guide/book is a good read for everyday Ubuntu user. The purpose of this book is to introduce you to the Ubuntu operating system, and the philosophy that underpins it. You can download a pdf version from the official site or order a print version using Amazon.
  1. Ubuntu pocket guide available in pdf and print formats.
  2. Support forums: No

#23: Linux: Rute User's Tutorial and Exposition


GNU/LINUX system administration book
GNU/Linux Book

This book covers GNU/LINUX system administration, for popular distributions like RedHat and Debian, as a tutorial for new users and a reference for advanced administrators. It aims to give concise, thorough explanations and practical examples of each aspect of a UNIX system. Anyone who wants a comprehensive text on (what is commercially called) LINUX need look no further--there is little that is not covered here.
  1. Linux: Rute User's Tutorial and Exposition available in print and html formats.
  2. Support forums: No

#24: Advanced Linux Programming


Advanced  Linux  Programming
Linux Programming

This book is intended for the programmer already familiar with the C programming language. It take a tutorial approach and teach the most important concepts and power features of the GNU/Linux system in application programs. If you're a developer already experienced with programming for the GNU/Linux system, are experienced with another UNIX-like system and are interested in developing GNU/Linux software, or want to make the transition for a non-UNIX environment and are already familiar with the general principles of writing good software, this book is for you. In addition, you will find that this book is equally applicable to C and C++ programming.
  1. Advanced Linux programming available in print and pdf formats.
  2. Support forums: No

#25: LPI 101 Course Notes


Linux Professional Institute Certification Books
LPIC books

LPIC-1/2/3 levels are certification for Linux administrators. This site provides training manuals for LPI 101 and 102 exams. These are licenced under the GNU Free Documentation Licence (FDL). This course material is based on the objectives for the Linux Professionals Institute’s LPI 101 and 102 examination. The course is intended to provide you with the skills required for operating and administering Linux systems.
  1. Download LPI training manuals in pdf format.
  2. Support forums: No

#26: FOSS Manuals

FLOSS Manuals is a collection of manuals about free and open source software together with the tools used to create them and the community that uses those tools. They include authors, editors, artists, software developers, activists, and many others. There are manuals that explain how to install and use a range of free and open source softwares, about how to do things (like design or stay safe online) with open source software, and manuals about free culture services that use or support free software and formats. You will find manuals about software such as VLC, Linux video editing, Linux, OLPC / SUGAR, GRAPHICS, and much more.
FLOSS Manuals is a collection of manuals about free and open source software
FLOSS Manuals: a collection of manuals about free and open source software
  1. You can browse FOSS manuals in wiki format.
  2. Support forums: No

#27: Linux Starter Pack


The Linux Starter Pack
Linux Starter Pack

New to the wonderful world of Linux? Looking for an easy way to get started? You can download 130-page guide and get to grips with the OS. This will show you how to install Linux onto your PC, navigate around the desktop, master the most popular Linux programs and fix any problems that may arise.
  1. Download Linux starter pack in pdf format.
  2. Support forums: No

#28: Linux.com - The Source of Linux Info

Linux.com is a product of the Linux Foundation. The side provides news, guides, tutorials and other information about Linux by harnessing the power of Linux users worldwide to inform, collaborate and connect on all matters Linux.
  1. Visit Linux.com online.
  2. Support forums: Yes

#29: LWN

LWN is a site with an emphasis on free software and software for Linux and other Unix-like operating systems. It consists of a weekly issue, separate stories which are published most days, and threaded discussion attached to every story. The site provide comprehensive coverage of development, legal, commercial, and security issues related to Linux and FOSS.
  1. Visit lwn.net online.
  2. Support forums: No

#30: Mac OS X Related sites

A quick links to Max OS X related sites:
  • Mac OS X Hints - This site is dedicated to the Apple's Mac OS X unix operating systems. It has tons of tips, tricks and tutorial about Bash, and OS X
  • Mac OS development library - Apple has good collection related to OS X development. Don't forget to checkout bash shell scripting primer.
  • Apple kbase - This is like RHN kbase. It provides guides and troublshooting tips for all apple products including OS X.

#30: NetBSD

NetBSD is another free open source operating system based upon the Berkeley Software Distribution (BSD) Unix operating system. The NetBSD project is primarily focused on high quality design, stability and performance of the system. Due to its portability and Berkeley-style license, NetBSD is often used in embedded systems. This site provides links to the official NetBSD documentation and also links to various external documents.
  1. View netbsd documentation online in html / pdf format.
  2. Support forums: No

/etc

  • GNU manuals - This site lists official GNU packages with links to their primary documentation, where available.
  • IBM AIX - If you are into an IBM enterprise grade hardware, AIX and big irons, than this is a must for you. On a related note don't forget to checkout IBM redbooks on Linux and Unix.
  • Another site dedicated to Debian GNU/Linux.
  • Safari Books Online's entire collection of over 18,000 books, training videos, rough cuts, short cuts, and articles from the world’s leading publishers is available online, in PDF format for chapter and whole-book downloads, or from your mobile device. This is not a free resource, but nevertheless quite useful for professionals.
  • Another introduction to the UNIX (and Linux) operating system and the UNIX - Level I course material.
  • Other suggestions made by nixCraft fans.
  • Google. Enough said.

Your Turn:

This is my personal list and it is not absolutely definitive, so if you've got your own favorite Unix/Linux specific site, share in the comments below.

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Crash course: Embedded programming with Arduino

Posted by Unknown Minggu, 25 Desember 2011 0 komentar

Try your hand at embedded programming with this project

Demand for embedded programming is growing like crazy, so anyone looking for some job security might consider becoming an ace embedded programmer. It helps to have some programming experience, but even raw beginners can get started inexpensively and learn on their own. One of the friendliest introductions to embedded coding is Arduino. Arduino is a popular open embedded hardware and software platform with hundreds of howtos and projects to try out. Today we review the basics of both electronics and Arduino coding in a fun holiday project, Singing Holiday Snowman.

Singing snowman

I'm going to take my old plastic snowman (figure 1) and outfit him to sing holiday songs whenever anyone approaches within a few feet, and to blink some festive red and green LEDs. (Half the fun of Arduino is blinky lights.) You, of course, may use any object you want. If you are new to electronics and embedded coding, give yourself a few days to put this together because it covers a lot of ground. This project gives hands-on experience in these essential fundamentals:

  • Soldering
  • Reading simple schematics
  • Loading and modifying Arduino programs


Figure 1: Plastic snowman before his operation, mute and unlit
Source: Carla Schroder

Prerequisites

The Singing Snowman is modeled on the Halloween Pumpkin project. Beginners should work through the first three of these excellent Arduino tutorials first. These will teach you how to install and use the Arduino software, and get acquainted with tools and Arduino parts. You'll be doing a fair bit of soldering; if you're not a good hand with a soldering iron, find some nothing-to-lose circuit boards and practice. The soldering page links to some good howtos.
Here is a handy hardware list. The first two items are nice kits that supply everything you need for Singing Snowman, plus leftovers for more projects.

  • Ladyada's Electronics Toolkit, $100. Includes a good adjustable temperature soldering iron, multimeter, snips, strippers, solder, solder sucker and braid, multimeter, vise, and other useful tools.
  • Adafruit ARDX - v1.3 Experimentation Kit. This includes red and green LEDs and matching resistors, printed howtos, breadboard, Arduino Uno, USB cable, wires, and other goodies for multiple projects. $85.
  • Adafruit Wave Shield for Arduino. This is the part that plays sounds. $22. You'll also need a SD/MMC card for storing audio files.
  • A small 8 ohm speaker, like an old PC speaker.
  • MaxBotix EZ1 sonar sensor. This will detect when someone is within a few feet of the snowman, and then it will play songs and animate the blinky lights. I use the MB1010 because it has a narrow sensitivity range to the front. There are three other versions with different sensitivity patterns.
  • Insulated 22-gauge solid-core wire in red, green, white, and black.
  • A magnifier and good light. I like magnifier lamps, and magnifier headlamps are nice too.
  • Wrist grounding strap. Arduino boards and accessories are pretty resilient to electrostatic discharge (ESD), but a strap is cheap insurance in a static-prone environment.
  • Drill and bits.
If you already have a well-equipped electronics workbench and don't need the two Adafruit kits, this is what you'll need for Singing Snowman:

  • Seven red and green LEDs with matching resistors
  • Arduino Uno
  • 9- or 12-volt power supply

Plus the other non-kit parts: Adafruit Wave Shield, MaxBotix EZ1, and wiring. Figure 2 shows my workbench with some of the tools and parts for this project.

Figure 2: Workbench for the singing holiday snowman project
Source: Carla Schroder

LEDs and resistors

You always need resistors with LEDs because resistors limit the current flowing to the LED to a safe level. Resistors are everywhere in electronics, and come in a huge variety of sizes and shapes. We are going to use through-hole carbon film resistors. A common beginner question is how do you know which resistors go with your LEDs? You need three pieces of information: The voltage of your power supply (Vs), and the voltage forward (Vf) and drive current (If) of the LED. Then calculate the resistor value (R), in ohms, like this: R = (Vs - Vf)/If.
For example, I have some of these 5mm red LEDs and a 9-volt power supply. So my equation is (9 - 1.85) / 0.02 = 357.5 ohms. The next highest standard resistor is 360 ohms at 1/2 watt, though most electronics gurus will go one higher and choose a 390 ohm resistor for a larger safety margin. A higher ohm value means more resistance and less current. You can damage LEDs with too much current. What does the watts value signify? That's how much power the resistor can handle. For low-power uses like our little blinky LEDS you'll see 1/8, 1/4, and 1/2 watt resistors. Try one of the many online LED calculators until you feel comfortable with your math, like this one.

Figure 3: The color-coding tells us this is a 390 ohm resistor
Source: Carla Schroder

That's for a single LED. We're using 7, so that changes our requirements. Again, there are handy online calculators to help us. The LED series/parallel array wizard calculates four different wiring layouts for you to choose from.
Resistors are color-coded. The color bars on the resistor in Figure 3 tell us this is rated at 390 ohms with 5% tolerance: Orange-White-Brown means 3-9- and one zero, or 390. The gold band = 5%. The tolerance rating is electronics-speak for plus/minus variance from the stated ohms.
Resistor color code tables are all over the place, on the Web and in books.

Assembly

The Wave Shield requires assembly and there is a lot of soldering, so do that first. When it's all together it will plug in nicely on top of your Arduino board. Then you'll solder your speaker and sonar sensor to the Wave board; follow the Halloween Pumpkin howto to see where the wires go. Make their wires long enough to allow you to mount the speaker and sensor where you want them inside your own project.
Use the LED series/parallel array wizard to figure out your LED wiring, and then solder your wiring harness together. Make sure your positive and negative leads are in correct order. The Halloween Pumpkin page says to use a glue gun to fasten the LEDs in place, but I prefer to drill holes that hold them snugly because it's less messy and easy to make changes. Once they're in place, solder the leads to the appropriate analog inputs and ground on your Wave board, and again leave enough slack in your wiring so you can move and easily access the Arduino and Wave Shield.
The clever part about the Halloween Pumpkin project is it saves a lot of code-writing by using an analog input to capture the audio output, which creates a variable-strength signal, and using that to animate the LEDs. Solder analog input #1 to the R7 1.5k resistor on the Wave board.
Plug your SD card into a PC in the usual way, with a card reader or built-in slot, and transfer your audio files to it. They must be in 22KHz 16-bit mono or lesser quality WAV. Then plug the card into the Wave Shield. Now you're ready to connect your PC to the Arduino with a USB cable, fire up the Arduino software, edit your sketch, and load it into the Arduino. One of Arduino's advantages is the speed of iteration -- you can quickly make and test changes in your code. Figure 4 shows my Singing Holiday Snowman in action.

Figure 4: Singing holiday snowman lit up and singing
Source: Carla Schroder

Arduino code

I'm using the Halloween Pumpkin sketch (an Arduino program is called a sketch) with some minor changes. The Arduino programming language is pretty much a slimmed-down C/C++. You will have to make some changes to this sketch, so look for my comments in the sketch which are enclosed in the standard C multi-line comment symbols, /* */. Single-line comments, which start with //, are the original comments from the original sketch author.
We covered a lot of ground in this Crash Course, and hopefully your project blinks and sings just the way you want. If something doesn't work right, and you can't figure it out, go back to the Arduino tutorials and review the basics, and the Arduino forums are a good source of help.

Additional references


Singing snowman sketch


#include 
#include
#include "util.h"
#include "wave.h"

AF_Wave card;
File f;
Wavefile wave;

// save RAM by using program memory strings
#define playcomplete(x) ROM_playcomplete(PSTR(x))

#define servo 7
#define redled 9
#define eyeleds 18
#define mouthleds 17
#define midmouthleds 16
#define outermouthleds 19

// set up Serial library at 9600 bps
void setup() {
Serial.begin(9600);
Serial.println("Wave test!");

/* Setup the LEDs */

pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(redled, OUTPUT);
pinMode(servo, OUTPUT);
pinMode(eyeleds, OUTPUT);
pinMode(outermouthleds, OUTPUT);
pinMode(midmouthleds, OUTPUT);
pinMode(mouthleds, OUTPUT);

randomSeed(analogRead(0));

/* Useful feedback if the SD card is missing
* or cannot be read */

if (!card.init_card()) {
putstring_nl("Card init. failed!"); return;
}
if (!card.open_partition()) {
putstring_nl("No partition!"); return;
}
if (!card.open_filesys()) {
putstring_nl("Couldn't open filesys"); return;
}

if (!card.open_rootdir()) {
putstring_nl("Couldn't open dir"); return;
}

putstring_nl("Files found:");
ls();
}

void ls() {
char name[13];
int ret;

card.reset_dir();
putstring_nl("Files found:");
while (1) {
ret = card.get_next_name_in_dir(name);
if (!ret) {
card.reset_dir();
return;
}
Serial.println(name);
}
}


void pulseServo(uint8_t servopin, uint16_t p) {

digitalWrite(servopin, HIGH);
delayMicroseconds(600);
while (p--) {
delayMicroseconds(4);
}
digitalWrite(servopin, LOW);
delay(18);
}

/* typedef unsigned char "snowmanstate"
* You can change this name to something
* suitable for your own project
* Measures how close people are and plays
* audio files according to distance */

uint8_t snowmanstate = 0;

void loop() {
int distsensor, i;
long time;
/*
for (i=0; i<50; i++) {
pulseServo(servo,0);
}
for (i=0; i<50; i++) {
pulseServo(servo,400);
}
return;
*/
distsensor = 0;
for (i=0; i<8; i++) {
distsensor += analogRead(0);
delay(50);
}
distsensor /= 8;

// putstring("Sensor = ");
Serial.println(distsensor);

/* A reading of 500 = more than 6 meters away, so once
* every 200 times play one of of three scary sounds
* when no one is present */

if (distsensor<= 500) {
digitalWrite(eyeleds, HIGH);
}
if (distsensor > 500) {
digitalWrite(eyeleds, LOW);

// nobody there. one out of 200 times play one of
// the scary sounds (once every few minutes)

/* Substitute your own audio file names */

snowmanstate = 1;
i = random(200);
//Serial.println(i);
if (i == 0) {
i = random(3);
if (i == 0) {
playcomplete("merryxmas.wav");
} else if (i == 1) {
playcomplete("hollyjolly.wav");
} else {
playcomplete("jinglebellsbatmansmells.wav");
}
}

/* When someone comes closer play these files
* Substitute your own audio file names */

} else if ((distsensor > 300) && (distsensor < 400)) {
if (snowmanstate <= 1) {
playcomplete("rudolph.wav");
} else {
i = random(60);
//Serial.println(i);
if (i == 0) {
i = random(3);
if (i == 0) {
playcomplete("frosty.wav");
} else if (i == 1) {
playcomplete("kissingsanta.wav");
} else {
playcomplete("deckhalls.wav");
}
}
}
snowmanstate = 2;
} else if ((distsensor > 100) && (distsensor < 200)) {
if (snowmanstate <= 2) {
playcomplete("frosty.wav");
} else {
i = random(50); // more often
//Serial.println(i);
if (i == 0) {
i = random(3);
if (i == 0) {
playcomplete("gotell.wav");
} else if (i == 1) {
playcomplete("joyworld.wav");
} else {
playcomplete("letitsnow.wav");
}
}
}
snowmanstate = 3;
} else if (distsensor < 50) {
if (snowmanstate <= 3) {
playcomplete("linussong.wav");
} else {
i = random(30); // more often
//Serial.println(i);
if (i == 0) {
i = random(2);
if (i == 0) {
playcomplete("mrgrinch.wav");
} else if (i == 1) {
playcomplete("sleighride.wav");
}
}

}
snowmanstate = 4;
}
}

/* This part lights the LEDs according to
* the strength of the audio signal */

void ROM_playcomplete(const char *romname) {
char name[13], i;
uint8_t volume;
int v2;

for (i=0; i <13; i++) {
name[i] = pgm_read_byte(&romname[i]);
}
name[12] = 0;
Serial.println(name);
playfile(name);
while (wave.isplaying) {
volume = 0;
for (i=0; i<8; i++) {
v2 = analogRead(1) - 512;
if (v2< 0)
v2 *= -1;
if (v2 > volume)
volume = v2;
delay(5);
}
if (volume > 200) {
digitalWrite(outermouthleds, HIGH);
} else {
digitalWrite(outermouthleds, LOW);
}
if (volume > 150) {
digitalWrite(midmouthleds, HIGH);
} else {
digitalWrite(midmouthleds, LOW);
}
if (volume > 100) {
digitalWrite(mouthleds, HIGH);
} else {
digitalWrite(mouthleds, LOW);
}
//putstring("vol = "); Serial.println(volume, DEC);
}
card.close_file(f);
}

void playfile(char *name) {
f = card.open_file(name);
if (!f) {
putstring_nl(" Couldn't open file"); return;
}
if (!wave.create(f)) {
putstring_nl(" Not a valid WAV"); return;
}
// ok time to play!
wave.play();
}

Baca Selengkapnya ....

20 Iptables Examples For New SysAdmins

Posted by Unknown 0 komentar

Linux comes with a host based firewall called Netfilter. According to the official project site:
netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack.
This Linux based firewall is controlled by the program called iptables to handles filtering for IPv4, and ip6tables handles filtering for IPv6. I strongly recommend that you first read our quick tutorial that explains how to configure a host-based firewall called Netfilter (iptables) under CentOS / RHEL / Fedora / Redhat Enterprise Linux. This post list most common iptables solutions required by a new Linux user to secure his or her Linux operating system from intruders.

IPTABLES Rules Example

  • Most of the actions listed in this post are written with the assumption that they will be executed by the root user running the bash or any other modern shell. Do not type commands on remote system as it will disconnect your access.
  • For demonstration purpose I've used RHEL 6.x, but the following command should work with any modern Linux distro.
  • This is NOT a tutorial on how to set iptables. See tutorial here. It is a quick cheat sheet to common iptables commands.

#1: Displaying the Status of Your Firewall

Type the following command as root:
# iptables -L -n -v
Sample outputs:
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Above output indicates that the firewall is not active. The following sample shows an active firewall:
# iptables -L -n -v
Sample outputs:
Chain INPUT (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 state INVALID
394 43586 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
93 17292 ACCEPT all -- br0 * 0.0.0.0/0 0.0.0.0/0
1 142 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
Chain FORWARD (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- br0 br0 0.0.0.0/0 0.0.0.0/0
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 state INVALID
0 0 TCPMSS tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp flags:0x06/0x02 TCPMSS clamp to PMTU
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 wanin all -- vlan2 * 0.0.0.0/0 0.0.0.0/0
0 0 wanout all -- * vlan2 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- br0 * 0.0.0.0/0 0.0.0.0/0
Chain OUTPUT (policy ACCEPT 425 packets, 113K bytes)
pkts bytes target prot opt in out source destination
Chain wanin (1 references)
pkts bytes target prot opt in out source destination
Chain wanout (1 references)
pkts bytes target prot opt in out source destination
Where,
  • -L : List rules.
  • -v : Display detailed information. This option makes the list command show the interface name, the rule options, and the TOS masks. The packet and byte counters are also listed, with the suffix 'K', 'M' or 'G' for 1000, 1,000,000 and 1,000,000,000 multipliers respectively.
  • -n : Display IP address and port in numeric format. Do not use DNS to resolve names. This will speed up listing.

#1.1: To inspect firewall with line numbers, enter:

# iptables -n -L -v --line-numbers
Sample outputs:
Chain INPUT (policy DROP)
num target prot opt source destination
1 DROP all -- 0.0.0.0/0 0.0.0.0/0 state INVALID
2 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
3 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
4 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
Chain FORWARD (policy DROP)
num target prot opt source destination
1 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
2 DROP all -- 0.0.0.0/0 0.0.0.0/0 state INVALID
3 TCPMSS tcp -- 0.0.0.0/0 0.0.0.0/0 tcp flags:0x06/0x02 TCPMSS clamp to PMTU
4 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
5 wanin all -- 0.0.0.0/0 0.0.0.0/0
6 wanout all -- 0.0.0.0/0 0.0.0.0/0
7 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
Chain OUTPUT (policy ACCEPT)
num target prot opt source destination
Chain wanin (1 references)
num target prot opt source destination
Chain wanout (1 references)
num target prot opt source destination
You can use line numbers to delete or insert new rules into the firewall.

#1.2: To display INPUT or OUTPUT chain rules, enter:

# iptables -L INPUT -n -v
# iptables -L OUTPUT -n -v --line-numbers

#2: Stop / Start / Restart the Firewall

If you are using CentOS / RHEL / Fedora Linux, enter:
# service iptables stop
# service iptables start
# service iptables restart

You can use the iptables command itself to stop the firewall and delete all rules:
# iptables -F
# iptables -X
# iptables -t nat -F
# iptables -t nat -X
# iptables -t mangle -F
# iptables -t mangle -X
# iptables -P INPUT ACCEPT
# iptables -P OUTPUT ACCEPT
# iptables -P FORWARD ACCEPT

Where,
  • -F : Deleting (flushing) all the rules.
  • -X : Delete chain.
  • -t table_name : Select table (called nat or mangle) and delete/flush rules.
  • -P : Set the default policy (such as DROP, REJECT, or ACCEPT).

#3: Delete Firewall Rules

To display line number along with other information for existing rules, enter:
# iptables -L INPUT -n --line-numbers
# iptables -L OUTPUT -n --line-numbers
# iptables -L OUTPUT -n --line-numbers | less
# iptables -L OUTPUT -n --line-numbers | grep 202.54.1.1

You will get the list of IP. Look at the number on the left, then use number to delete it. For example delete line number 4, enter:
# iptables -D INPUT 4
OR find source IP 202.54.1.1 and delete from rule:
# iptables -D INPUT -s 202.54.1.1 -j DROP
Where,
  • -D : Delete one or more rules from the selected chain

#4: Insert Firewall Rules

To insert one or more rules in the selected chain as the given rule number use the following syntax. First find out line numbers, enter:
# iptables -L INPUT -n --line-numbers
Sample outputs:
Chain INPUT (policy DROP)
num target prot opt source destination
1 DROP all -- 202.54.1.1 0.0.0.0/0
2 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state NEW,ESTABLISHED
To insert rule between 1 and 2, enter:
# iptables -I INPUT 2 -s 202.54.1.2 -j DROP
To view updated rules, enter:
# iptables -L INPUT -n --line-numbers
Sample outputs:
Chain INPUT (policy DROP)
num target prot opt source destination
1 DROP all -- 202.54.1.1 0.0.0.0/0
2 DROP all -- 202.54.1.2 0.0.0.0/0
3 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state NEW,ESTABLISHED

#5: Save Firewall Rules

To save firewall rules under CentOS / RHEL / Fedora Linux, enter:
# service iptables save
In this example, drop an IP and save firewall rules:
# iptables -A INPUT -s 202.5.4.1 -j DROP
# service iptables save

For all other distros use the iptables-save command:
# iptables-save > /root/my.active.firewall.rules
# cat /root/my.active.firewall.rules

#6: Restore Firewall Rules

To restore firewall rules form a file called /root/my.active.firewall.rules, enter:
# iptables-restore < /root/my.active.firewall.rules
To restore firewall rules under CentOS / RHEL / Fedora Linux, enter:
# service iptables restart

#7: Set the Default Firewall Policies

To drop all traffic:
# iptables -P INPUT DROP
# iptables -P OUTPUT DROP
# iptables -P FORWARD DROP
# iptables -L -v -n
#### you will not able to connect anywhere as all traffic is dropped ###
# ping cyberciti.biz
# wget http://www.kernel.org/pub/linux/kernel/v3.0/testing/linux-3.2-rc5.tar.bz2

#7.1: Only Block Incoming Traffic

To drop all incoming / forwarded packets, but allow outgoing traffic, enter:
# iptables -P INPUT DROP
# iptables -P FORWARD DROP
# iptables -P OUTPUT ACCEPT
# iptables -A INPUT -m state --state NEW,ESTABLISHED -j ACCEPT
# iptables -L -v -n
### *** now ping and wget should work *** ###
# ping cyberciti.biz
# wget http://www.kernel.org/pub/linux/kernel/v3.0/testing/linux-3.2-rc5.tar.bz2

#8:Drop Private Network Address On Public Interface

IP spoofing is nothing but to stop the following IPv4 address ranges for private networks on your public interfaces. Packets with non-routable source addresses should be rejected using the following syntax:
# iptables -A INPUT -i eth1 -s 192.168.0.0/24 -j DROP
# iptables -A INPUT -i eth1 -s 10.0.0.0/8 -j DROP

#8.1: IPv4 Address Ranges For Private Networks (make sure you block them on public interface)

  • 10.0.0.0/8 -j (A)
  • 172.16.0.0/12 (B)
  • 192.168.0.0/16 (C)
  • 224.0.0.0/4 (MULTICAST D)
  • 240.0.0.0/5 (E)
  • 127.0.0.0/8 (LOOPBACK)

#9: Blocking an IP Address (BLOCK IP)

To block an attackers ip address called 1.2.3.4, enter:
# iptables -A INPUT -s 1.2.3.4 -j DROP
# iptables -A INPUT -s 192.168.0.0/24 -j DROP

#10: Block Incoming Port Requests (BLOCK PORT)

To block all service requests on port 80, enter:
# iptables -A INPUT -p tcp --dport 80 -j DROP
# iptables -A INPUT -i eth1 -p tcp --dport 80 -j DROP

To block port 80 only for an ip address 1.2.3.4, enter:
# iptables -A INPUT -p tcp -s 1.2.3.4 --dport 80 -j DROP
# iptables -A INPUT -i eth1 -p tcp -s 192.168.1.0/24 --dport 80 -j DROP

#11: Block Outgoing IP Address

To block outgoing traffic to a particular host or domain such as cyberciti.biz, enter:
# host -t a cyberciti.biz
Sample outputs:
cyberciti.biz has address 75.126.153.206
Note down its ip address and type the following to block all outgoing traffic to 75.126.153.206:
# iptables -A OUTPUT -d 75.126.153.206 -j DROP
You can use a subnet as follows:
# iptables -A OUTPUT -d 192.168.1.0/24 -j DROP
# iptables -A OUTPUT -o eth1 -d 192.168.1.0/24 -j DROP

#11.1: Example - Block Facebook.com Domain

First, find out all ip address of facebook.com, enter:
# host -t a www.facebook.com
Sample outputs:
www.facebook.com has address 69.171.228.40
Find CIDR for 69.171.228.40, enter:
# whois 69.171.228.40 | grep CIDR
Sample outputs:
CIDR:           69.171.224.0/19
To prevent outgoing access to www.facebook.com, enter:
# iptables -A OUTPUT -p tcp -d 69.171.224.0/19 -j DROP
You can also use domain name, enter:
# iptables -A OUTPUT -p tcp -d www.facebook.com -j DROP
# iptables -A OUTPUT -p tcp -d facebook.com -j DROP

From the iptables man page:
... specifying any name to be resolved with a remote query such as DNS (e.g., facebook.com is a really bad idea), a network IP address (with /mask), or a plain IP address ...

#12: Log and Drop Packets

Type the following to log and block IP spoofing on public interface called eth1
# iptables -A INPUT -i eth1 -s 10.0.0.0/8 -j LOG --log-prefix "IP_SPOOF A: "
# iptables -A INPUT -i eth1 -s 10.0.0.0/8 -j DROP

By default everything is logged to /var/log/messages file.
# tail -f /var/log/messages
# grep --color 'IP SPOOF' /var/log/messages

#13: Log and Drop Packets with Limited Number of Log Entries

The -m limit module can limit the number of log entries created per time. This is used to prevent flooding your log file. To log and drop spoofing per 5 minutes, in bursts of at most 7 entries .
# iptables -A INPUT -i eth1 -s 10.0.0.0/8 -m limit --limit 5/m --limit-burst 7 -j LOG --log-prefix "IP_SPOOF A: "
# iptables -A INPUT -i eth1 -s 10.0.0.0/8 -j DROP

#14: Drop or Accept Traffic From Mac Address

Use the following syntax:
# iptables -A INPUT -m mac --mac-source 00:0F:EA:91:04:08 -j DROP
## *only accept traffic for TCP port # 8080 from mac 00:0F:EA:91:04:07 * ##
# iptables -A INPUT -p tcp --destination-port 22 -m mac --mac-source 00:0F:EA:91:04:07 -j ACCEPT

#15: Block or Allow ICMP Ping Request

Type the following command to block ICMP ping requests:
# iptables -A INPUT -p icmp --icmp-type echo-request -j DROP
# iptables -A INPUT -i eth1 -p icmp --icmp-type echo-request -j DROP

Ping responses can also be limited to certain networks or hosts:
# iptables -A INPUT -s 192.168.1.0/24 -p icmp --icmp-type echo-request -j ACCEPT
The following only accepts limited type of ICMP requests:
### ** assumed that default INPUT policy set to DROP ** #############
iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT
iptables -A INPUT -p icmp --icmp-type destination-unreachable -j ACCEPT
iptables -A INPUT -p icmp --icmp-type time-exceeded -j ACCEPT
## ** all our server to respond to pings ** ##
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT

#16: Open Range of Ports

Use the following syntax to open a range of ports:
iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 7000:7010 -j ACCEPT

#17: Open Range of IP Addresses

Use the following syntax to open a range of IP address:
## only accept connection to tcp port 80 (Apache) if ip is between 192.168.1.100 and 192.168.1.200 ##
iptables -A INPUT -p tcp --destination-port 80 -m iprange --src-range 192.168.1.100-192.168.1.200 -j ACCEPT

## nat example ##
iptables -t nat -A POSTROUTING -j SNAT --to-source 192.168.1.20-192.168.1.25

#17: Established Connections and Restaring The Firewall

When you restart the iptables service it will drop established connections as it unload modules from the system under RHEL / Fedora / CentOS Linux. Edit, /etc/sysconfig/iptables-config and set IPTABLES_MODULES_UNLOAD as follows:
IPTABLES_MODULES_UNLOAD = no

#18: Help Iptables Flooding My Server Screen

Use the crit log level to send messages to a log file instead of console:
iptables -A INPUT -s 1.2.3.4 -p tcp --destination-port 80 -j LOG --log-level crit

#19: Block or Open Common Ports

The following shows syntax for opening and closing common TCP and UDP ports:
 
Replace ACCEPT with DROP to block port:
## open port ssh tcp port 22 ##
iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 22 -j ACCEPT
 
## open cups (printing service) udp/tcp port 631 for LAN users ##
iptables -A INPUT -s 192.168.1.0/24 -p udp -m udp --dport 631 -j ACCEPT
iptables -A INPUT -s 192.168.1.0/24 -p tcp -m tcp --dport 631 -j ACCEPT
 
## allow time sync via NTP for lan users (open udp port 123) ##
iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p udp --dport 123 -j ACCEPT
 
## open tcp port 25 (smtp) for all ##
iptables -A INPUT -m state --state NEW -p tcp --dport 25 -j ACCEPT
 
# open dns server ports for all ##
iptables -A INPUT -m state --state NEW -p udp --dport 53 -j ACCEPT
iptables -A INPUT -m state --state NEW -p tcp --dport 53 -j ACCEPT
 
## open http/https (Apache) server port to all ##
iptables -A INPUT -m state --state NEW -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -m state --state NEW -p tcp --dport 443 -j ACCEPT
 
## open tcp port 110 (pop3) for all ##
iptables -A INPUT -m state --state NEW -p tcp --dport 110 -j ACCEPT
 
## open tcp port 143 (imap) for all ##
iptables -A INPUT -m state --state NEW -p tcp --dport 143 -j ACCEPT
 
## open access to Samba file server for lan users only ##
iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 137 -j ACCEPT
iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 138 -j ACCEPT
iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 139 -j ACCEPT
iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 445 -j ACCEPT
 
## open access to proxy server for lan users only ##
iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 3128 -j ACCEPT
 
## open access to mysql server for lan users only ##
iptables -I INPUT -p tcp --dport 3306 -j ACCEPT
 

#20: Restrict the Number of Parallel Connections To a Server Per Client IP

You can use connlimit module to put such restrictions. To allow 3 ssh connections per client host, enter:
# iptables -A INPUT -p tcp --syn --dport 22 -m connlimit --connlimit-above 3 -j REJECT
Set HTTP requests to 20:
# iptables -p tcp --syn --dport 80 -m connlimit --connlimit-above 20 --connlimit-mask 24 -j DROP
Where,
  1. --connlimit-above 3 : Match if the number of existing connections is above 3.
  2. --connlimit-mask 24 : Group hosts using the prefix length. For IPv4, this must be a number between (including) 0 and 32.

#21: HowTO: Use iptables Like a Pro

For more information about iptables, please see the manual page by typing man iptables from the command line:
$ man iptables
You can see the help using the following syntax too:
# iptables -h
To see help with specific commands and targets, enter:
# iptables -j DROP -h

#21.1: Testing Your Firewall

Find out if ports are open or not, enter:
# netstat -tulpn
Find out if tcp port 80 open or not, enter:
# netstat -tulpn | grep :80
If port 80 is not open, start the Apache, enter:
# service httpd start
Make sure iptables allowing access to the port 80:
# iptables -L INPUT -v -n | grep 80
Otherwise open port 80 using the iptables for all users:
# iptables -A INPUT -m state --state NEW -p tcp --dport 80 -j ACCEPT
# service iptables save

Use the telnet command to see if firewall allows to connect to port 80:
$ telnet www.cyberciti.biz 80
Sample outputs:
Trying 75.126.153.206...
Connected to www.cyberciti.biz.
Escape character is '^]'.
^]
telnet> quit
Connection closed.
You can use nmap to probe your own server using the following syntax:
$ nmap -sS -p 80 www.cyberciti.biz
Sample outputs:
Starting Nmap 5.00 ( http://nmap.org ) at 2011-12-13 13:19 IST
Interesting ports on www.cyberciti.biz (75.126.153.206):
PORT STATE SERVICE
80/tcp open http
Nmap done: 1 IP address (1 host up) scanned in 1.00 seconds
I also recommend you install and use sniffer such as tcpdupm and ngrep to test your firewall settings.

Conclusion:

This post only list basic rules for new Linux users. You can create and build more complex rules. This requires good understanding of TCP/IP, Linux kernel tuning via sysctl.conf, and good knowledge of your own setup. Stay tuned for next topics:
  • Stateful packet inspection.
  • Using connection tracking helpers.
  • Network address translation.
  • Layer 2 filtering.
  • Firewall testing tools.
  • Dealing with VPNs, DNS, Web, Proxy, and other protocols.

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symbel pemutar musik

Posted by Unknown Jumat, 09 Desember 2011 0 komentar
adalah pemutar musik versi 1.0 dengan kosep multifungsi, didesain menyerupai handphone nokia
zaman dulu .diluncurkan pada desember 2011
software ini akan menentukan kelanjutan dari versinya sendiri, untuk awal hanya
akan menentukan rating sekitar 30% dan nantinya akan lebih dikembangkan lagi
kelebihan fitur ini antara lain, dapat berjalan disegala macam windows, ukuran yang kecil,
proses yang dibutuhkan sangat kecil dibandingkan penutar musik lain

kekuarngannya antara lain, fitur yang masih sangat sederhana dan belum tersedianya pengaturan untuk suara,
fitur kamera yang hanya dapat berjalan di produk acer.
over all, untuk yang hanya ingin mendengar musik dan mementingkan performa komputer, software inilah
yang paling tepat.

ini sekilas screenshotnnya




bagi yang minat silahkan download disini

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asal kata debug pada windows

Posted by Unknown Senin, 05 Desember 2011 0 komentar
debug berasal dari bhasa inggris "bug" yang bila diartikan dalam bahasa indonesia adalah"sarangga",sajerah
singkatnya seperti berikut:Tahun 1945, Grace Murray Hopper dan timnya sedang bekerja pada komputer kalkulator Relay Aiken Mark II University Hardvard. Lalu komputernya bermasalah. Setelah dicari penyebabnya, ternyata ada lebah pada Relay #70 di panel F. Lebah tersebut kemudian disingkirkan. nah, untuk debug sendiri merupakan istilah penanggulangan dari bug, yaitu proses perbaikan suatu program yang mengalami kerusakan atau jika memang tidak bisa diperbaiki maka komputer akan otomatis mematikan program tersebut.debug sendiri sering kita jumpai di task manager, atau apa bila ada program yang tidak berjalan semestinya , warning untuk debug akan muncul, karena yang dimaksud bug dalam komputer bukanlah serangga dalam arti yang sebenarnya, tapi merupakan kesalahan yang terjadi pada suatu program yang tidak berjalan semestinya karena suatu faktor, bisa saja karena salah penulisan script atau karena minimal spesifikasi yang tidak cocok.

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