Sharing is the best thing in life.: February 2008

Thursday, February 28, 2008

Learn to speak English Deluxe 9.0

Install Upgrade MySQL 5 on Redhat Enterprise version 4 (RHEL4)

Upgrade MySQL 4.1 to 5.0 on RHEL4:
With Debian(Ubuntu) install and upgrade are very easy but on Fedora or Redhat it very difficult.
On Redhat Enterprise 4.0 before upgrade MySQl 4.1 to MySQL 5.0 you must uninstall MySql 4.1 first.
You can follow these command :

#rpm -e mysql-devel-4.1.7-4.RHEL4.1.i386
#rpm -e mysql-server-4.1.7-4.RHEL4.1.i386
#rpm -e mysql-4.1.7-4.RHEL4.1

After you removed old MySQL 4.1 you need download these packages:
MySQL-shared-compat-5.0.51a-0.rhel4.i386.rpm,MySQL-devel-community-5.0.51a-0.rhel4.i386.rpm,MySQL-server-community-5.0.51a-0.rhel4.i386.rpm ,MySQL-client-community-5.0.51a-0.rhel4.i386.rpm
It can be download on website mysql:
http://dev.mysql.com/downloads/mysql/5.0.html#
when downloaded you enter these command:

#rpm -ivh MySQL-shared-compat-5.0.51a-0.rhel4.i386.rpm
#rpm -ivh MySQL-devel-community-5.0.51a-0.rhel4.i386.rpm
#rpm -ivh MySQL-server-community-5.0.51a-0.rhel4.i386.rpm
#rpm -ivh MySQL-client-community-5.0.51a-0.rhel4.i386.rpm

At the Terminal :when you entered command mysql
it can be show this:

Your MySQL connection id is 13
Server version: 5.0.51a-community MySQL Community Edition (GPL)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql>

Congratulations,You have Mysql 5.0 Installed
(I'm so sorry if I make mistake in English Grammar)

Wednesday, February 27, 2008

VoIP Security

McGrawHill Hacking...

Hosted by eSnips

Syngress How to Ch...

Hosted by eSnips

Asterisk Stability...

Hosted by eSnips

Voice over IP (VoIP) has finally come of age and is being rapidly embraced across most markets as an alternative to the traditional public-switched telephone network (PSTN). VoIP is a broad term, describing many different types of applications (hard phones, softphones, proxy servers, Instant Messaging clients, peer-to-peer clients, and so on), installed on a wide variety of platforms (Linux, Windows, VxWorks, mobile devices, PCs, and so on), and using a wide variety of both proprietary and open protocols (SIP, RTP, H.323, MGCP, SCCP, Unistim, SRTP, ZRTP, and so on) that depend heavily on your preexisting data network's infrastructure and services (routers, switches, DNS, TFTP, DHCP, VPNs, VLANs and so on). Correspondingly, VoIP security is just as broad a subject thanks to the heterogeneous nature of these environments found in the consumer, enterprise, carrier, and small/medium–sized business markets.

How the Book is Organized

This book is split into five completely different parts. Each part can be read without even touching the remaining four—so if the reader is interested only in the issues described in the selected part, he or she may consult only that part.

Part I. "Casing the Establishment"

The first part is introductory and describes how an attacker would first scan the whole network and then pick up specific targets and enumerate them with great precision in order to proceed with further advanced attacks through or from the hacked VoIP devices.

Chapter 1. "Footprinting a VoIP Network"

We begin the book by describing how a hacker first profiles the target organization by performing passive reconnaissance using tools such as Google, DNS, and WHOIS records, as well as the target's own website.

Chapter 2. "Scanning a VoIP Network"

A logical continuation of the previous chapter, this chapter provides a review of various remote scanning techniques in order to identify potentially active VoIP devices on the network. We cover the traditional UDP, TCP, SNMP, and ICMP scanning techniques as applied to VoIP devices.

Chapter 3. "Enumerating a VoIP Network"

Here, we show active methods of enumeration of various standalone VoIP devices, from softphones, hard phones, proxies, and other general SIP-enabled devices. Plenty of examples are provided, along with a demonstration of SIPScan, a SIP directory scanning tool we wrote.

Part II. "'Exploiting the VoIP Network"

This part of the book is focused on exploiting the supporting network infrastructure on which your VoIP applications depend. We begin with typical network denial-of-service attacks and eventually lead up to VoIP conversation eavesdropping. While many of the demonstrated techniques originate from the traditional data security world, we applied them against VoIP devices and supporting network services.

Chapter 4. "VoIP Network Infrastructure Denial of Service (DoS)"

In this chapter, we introduce quality of service and how to objectively measure the quality of a VoIP conversation on the network using various free and commercial tools. Next, we discuss various flooding and denial of service attacks on VoIP devices and supporting services such as DNS and DHCP.

Chapter 5. "VoIP Network Eavesdropping"

This section is very much focused on the types of VoIP privacy attacks an attacker can perform with the appropriate network access to sniff traffic. Techniques such as number harvesting, call pattern tracking, TFTP file snooping, and actual conversation eavesdropping are demonstrated.

Chapter 6. "VoIP Interception and Modification"

The methods described in this chapter detail how to perform man-in-the-middle attacks in order to intercept and alter an active VoIP session and conversation. We demonstrate some man-in-the-middle methods of ARP poisoning and present a new tool called sip_rogue that can sit in between two calling parties and monitor or alter their session and conversation.

Part III. "Exploiting Specific VoIP Platforms"

In this part of the book, we shift our attention to attacking specific vendor platforms where each has unique security weaknesses and countermeasures. We demonstrate some of the attacks covered in the last few chapters in order to detail the vendor-specific best practices for mitigating them.

Chapter 7. "Cisco Unified CallManager"

We installed Cisco CallManager 4.x with Cisco hard phones in a fully homogenous Cisco-switched environment in order to perform many of the attacks we've already detailed.

We also cover the various best practices to apply to the Cisco switching gear to mitigate most of the network attacks covered in Part II.

Chapter 8. "Avaya Communication Manager"

Similarly, we installed a full Avaya Communication Manager along with Avaya hard phones to detail some of the specific attacks we covered in Part I and Part II.

Chapter 9. "Asterisk"

We targeted our SIP test bed running Asterisk with the similar attacks detailed in Part I and Part II. We also performed some basic platform testing on a subset of the SIP phones in our test bed.

Chapter 10. "Emerging Softphone Technologies"

In this chapter, we discuss some security issues with the emerging softphone services, such as Skype, Gizmo, and others. While these services have not yet dominantly emerged into the enterprise space, they are poised to do so through some interesting partnerships under way.

Part IV. "VoIP Session and Application Hacking"

In this part of the book, we shift our attention from attacking the network and device to attacking the protocol. The fine art of protocol exploitation can hand intruders full control over the VoIP application traffic without any direct access and reconfiguration of the hosts or phones deployed.

Chapter 11. "Fuzzing VoIP"

The practice of fuzzing, otherwise known as robustness testing or functional protocol testing, has been around for a while in the security community. The practice has proven itself to be pretty effective at automating vulnerability discovery in applications and devices that support a target protocol. In this chapter, we demonstrate some tools and techniques for fuzzing your VoIP applications.

Chapter 12. "Flood-Based Disruption of Service"

In this chapter, we cover additional attacks that disrupt SIP proxies and phones by flooding them with various types of VoIP protocol and session-specific messages. These types of attacks partially or totally disrupt service for a SIP proxy or phone while the attack is under way. Some of the attacks actually cause the target to go out of service, requiring a restart.

Chapter 13. "Signaling and Media Manipulation"

In this chapter, we cover other attacks in which an attacker manipulates SIP signaling or RTP media to hijack, terminate, or otherwise manipulate calls. We introduce no less than ten new tools to demonstrate these attacks. As with other attacks we have covered, these attacks are simple to execute and quite lethal.

Part V. "Social Threats"

In the same way that the traditional email realm has been inundated with spam and phishing, so too are we starting to see the evolution of these social nuisances into the VoIP world. This chapter focuses on how advertisers and scam artists will likely target VoIP users and how to help counter their advance.

Chapter 14. "SPAM over Internet Telephony (SPIT)"

Voice SPAM or SPAM over Internet Telephony (SPIT) is a similar problem that will affect VoIP. SPIT, in this context, refers to bulk, automatically generated, unsolicited calls. SPIT is like telemarketing on steroids. You can expect SPIT to occur with a frequency similar to email SPAM. This chapter describes how you can use the Asterisk IP PBX and a new tool called spitter to generate your own SPIT. This chapter also details how you can detect and mitigate SPIT.

Chapter 15. "Voice Phishing"

Voice phishing relies on the effective gullibility of a victim trusting a phone number much more than an email link. Also, for a fraction of the cost, an attacker can set up an interactive voice response system through a VoIP provider that is harder to trace than a compromised web server. Also, the nature of VoIP makes this type of attack even more feasible because most VoIP services grant their customers an unlimited number of calls for a monthly fee. This chapter details how these attacks are performed and how to detect them at their various stages.

TOEFL IBT ALL-IN-ONE (AIO)

This package contains materials that are required for those who prepare for TOEFL-iBT exam. I have collected the materials for iBT alone. The unpacked size will be 3GB in size. The compressed one comes around 2.57GB in size.
Contents
Barron's TOEFL CD+ 10 Audio CDs
Barron's passkey to the TOEFL-iBT
Kaplan TOEFL-iBT with CD-ROM 2007-08 Edition
Longman's TOEFL-iBT
ETS-TOEFL official Guide+ Audio CD
New Cambridge preparation for TOEFL
Mastering skills for the TOEFL-iBT
Cracking TOEFL listening
400 Must-have Words for the TOEFL.pdf
Answers to all TOEFL Essay Questions.pdf
BARRONS How to Prepare For TOEFL 11ed.pdf
English Advanced Grammar in Use.pdf
TOEFL Exam Success In Only 6 Steps.pdf
TOEFL Exam Essentials.pdf

links
http://rapidshare.com/files/72717703/TOEFL_IBT_AIO.part01.rar
http://rapidshare.com/files/72718451/TOEFL_IBT_AIO.part02.rar
http://rapidshare.com/files/72719543/TOEFL_IBT_AIO.part03.rar
http://rapidshare.com/files/72720151/TOEFL_IBT_AIO.part04.rar
http://rapidshare.com/files/72720794/TOEFL_IBT_AIO.part05.rar
http://rapidshare.com/files/72721665/TOEFL_IBT_AIO.part06.rar
http://rapidshare.com/files/72722781/TOEFL_IBT_AIO.part07.rar
http://rapidshare.com/files/72723579/TOEFL_IBT_AIO.part08.rar
http://rapidshare.com/files/72724306/TOEFL_IBT_AIO.part09.rar
http://rapidshare.com/files/72725090/TOEFL_IBT_AIO.part10.rar
http://rapidshare.com/files/72726388/TOEFL_IBT_AIO.part11.rar
http://rapidshare.com/files/72727248/TOEFL_IBT_AIO.part12.rar
http://rapidshare.com/files/72730800/TOEFL_IBT_AIO.part13.rar
http://rapidshare.com/files/72731492/TOEFL_IBT_AIO.part14.rar
http://rapidshare.com/files/72732243/TOEFL_IBT_AIO.part15.rar
http://rapidshare.com/files/72733754/TOEFL_IBT_AIO.part16.rar
http://rapidshare.com/files/72734829/TOEFL_IBT_AIO.part17.rar
http://rapidshare.com/files/72735662/TOEFL_IBT_AIO.part18.rar
http://rapidshare.com/files/72736137/TOEFL_IBT_AIO.part19.rar
http://rapidshare.com/files/72736923/TOEFL_IBT_AIO.part20.rar
http://rapidshare.com/files/72738031/TOEFL_IBT_AIO.part21.rar
http://rapidshare.com/files/72738652/TOEFL_IBT_AIO.part22.rar
http://rapidshare.com/files/72740198/TOEFL_IBT_AIO.part23.rar
http://rapidshare.com/files/72740784/TOEFL_IBT_AIO.part24.rar
http://rapidshare.com/files/72741347/TOEFL_IBT_AIO.part25.rar
http://rapidshare.com/files/72742181/TOEFL_IBT_AIO.part26.rar
http://rapidshare.com/files/72742927/TOEFL_IBT_AIO.part27.rar
http://rapidshare.com/files/72743404/TOEFL_IBT_AIO.part28.rar
97,280KB x 27 files + 75,317KB x 1 file [97Mb x 27 + 75Mb x 1]
No password required.

Ultra ISO enclosed for viewing CD files after installation within appropriate
folders that require CD on drive with specific label that can not be labelled using
Nero CD writing software [long CD label name]
Good collection of Audio CDs , model tests with time mode, listening, writing and speaking
practice etc.
A good collection of pdf books are also included which are specifically for iBT tests

The Best Things in Life

Falling in love.
Laughing so hard your face hurts.
A hot shower.
No lines at the Super Wal-Mart.
A special glance.
Getting mail.
Taking a drive on a pretty road.
Hearing your favorite song on the radio.
Lying in bed listening to the rain outside.
Hot towels out of the dryer.
Finding the sweater you want is on sale for half price.
Chocolate milkshake.
A long distance phone call.
A bubble bath.
Giggling.
A good conversation.
The beach.
Finding a $20 bill in your coat from last winter.
Laughing at yourself.
Midnight phone calls that last for hours.
Running through sprinklers.
Laughing for absolutely no reason at all.
Having someone tell you that you're beautiful.
Laughing at an inside joke.
Friends.
Falling in love for the first time.
Accidentally overhearing someone say something nice about you.
Waking up and realizing you still have a few hours left to sleep.
Your first kiss.
Making new friends or spending time with old ones.
Playing with a new puppy.
Late night talks with your roommate that keep you from sleeping.
Having someone play with your hair.
Sweet dreams.
Hot chocolate.
Road trips with friends.
Swinging on swings.
Watching a good movie cuddled up on a couch with someone you love.
Wrapping presents under the Christmas tree while eating cookies and drinking eggnog.
Song lyrics printed inside your new CD so you can sing along without feeling stupid.
Going to a really good concert.
Getting butterflies in your stomach every time you see that one person.
Making eye contact with a cute stranger.
Winning a really competitive game.
Making chocolate chip cookies!
Having your friends send you homemade cookies!
Spending time with close friends!
Seeing smiles and hearing laughter from your friends.
Holding hands with someone you care about.
Running into an old friend and realizing that some things (good or bad) never change.
Discovering that love is unconditional and stronger than time.
Riding the best roller coasters over and over.
Hugging the person you love.
Watching the expression someone's face as they open a much-desired present from you.
Watching the sunrise.
Getting out of bed every morning and thanking God for another beautiful day.
Having friends you know you can cry on or talk to about your deepest problems

The Princeton Review Cracking the TOEFL 2007 edition

Author: Douglas Pierce, Sean Kinsell
Publisher: Princeton
File size: 60.3 + 57 Mb
File type: pdf in rar

The Princeton Review

Cracking the TOEFL 2007 edition

In Cracking the TOEFL iBT, The Princeton Review will teach you how to

·Use our preparation strategies and test-taking techniques to raise your score
·Focus your reading and listening to identify the key parts of passages, lectures, and conversations
·Improve your command of spoken English and your use of good English grammar and vocabulary
·Write top-scoring essays by responding to the specific question asked and organizing your ideas clearly
·Test your knowledge with review questions and practice drills for each topic covered

All of our practice test questions are just like those on the actual exam, and we explain how to answer every question.

Download:

The book:

http://mihd.net/0fo2ci

http://rapidshare.com/files/75766243/PT8.rar

Audio CD:

http://www.vanandy.com/plus/download.php?open=1&link=L3VwaW1nL3NvZnQvMjAwNzAzMjcwMDU0LnJhcg%3D%3D

http://rapidshare.com/files/75839765/200703270054.rar

Developing Skills for the TOEFL iBT

(Intermediate)
Developing Skills for the iBT TOEFL continues the Compass graded test preparation course designed to hone the test-taking skills required of students who will take the TOEFL iBT administered by ETS. In this second book of the series, students will be able to familiarize themselves with innovative question types found on the TOEFL iBT test in addtion to practicing suggested tips and skills designed to increase their test scores in all four skill-based test sections: reading, listening, speaking, and writing.
Download here 10 CDs

Download:

Free downloading:

Writing: 1CD - 20 MB
http://www.compasspub.com/mp3file/Developing_Writing.zip

Speaking: 2CD - 54 MB
http://www.compasspub.com/mp3file/Developing_Speaking.zip

Listening: 6CD - 155 MB
http://www.compasspub.com/mp3file/Developing_Listening.zip

Answer keys-Transcript
http://www.compasspub.com/korean/support/AnswerKey/?goodkey=524

Mirrors:

http://rapidfolder.com/?T9BN6

http://mihd.net/t08kyg
http://mihd.net/5bkrde
http://mihd.net/42o3qa
http://mihd.net/vemwp4
http://mihd.net/jp7f69
http://mihd.net/ozst92
http://mihd.net/isch6v
http://mihd.net/5ed8k9
http://mihd.net/nlxekv
http://mihd.net/uc4qve

Mastering Skills for the TOEFL iBT (2006)

(Advanced)

Writing: 1CD - 23.46 MB
http://www.compasspub.com/mp3file/Mastering_Writing.zip

Speaking: 2CD - 57 MB
http://www.compasspub.com/mp3file/Mastering_Speaking.zip

Listening: 6CD - 196.8 MB
http://www.compasspub.com/mp3file/Mastering_Listening.zip

Answer keys-Transcript
http://www.compasspub.com/korean/support/AnswerKey/?goodkey=52

Tuesday, February 26, 2008

Fax Over IP (Part II)

FoIP Software Architecture
The facsimile interface unit (FIU) is the software module that resides within a
FoIP IWF. It demodulates voiceband signals from an analog interface and
converts them to a digital format suitable for transport over a packet network. It
also remodulates data received from the packet network and transmits it to the
analog interface. In doing so, the FIU performs protocol conversion between
Group-3 facsimile protocols and the digital facsimile protocol employed over the
packet network.
The FIU, shown in Figure 10, consists of the following three units:
fax-modem unit (FM)—This processes PCM samples based on the current
modulation mode and supports the following functions:
• V.21 Channel 2 (300 bps) binary signaling modulation and
demodulation
• high-level data link control (HDLC) framing (0 bit insertion/removal,
cyclic redundancy check (CRC) generation/checking)
• V.27 ter (2400/4800 bps) high-speed data modulation and
demodulation
• V.29 (7200/9600 bps) high-speed data modulation and demodulation
• V.17 (7200/9600/12000/14400 bps) high-speed data modulation and
demodulation
• V.33 (12000/14400 bps) high-speed modulation and demodulation
• CED detection and generation
• CNG detection and generation
• V.21 Channel-2 detection

Monday, February 25, 2008

CURRICULUM VITAE

CURRICULUM VITAE

--------- & --------

Personal information:
Full name :
Data of birth :
Place of birth :
Sex : Male
Address :
Mobil :
Email :
Education:
From 2002-2007: Study in Hanoi university of technology, specialized in Printing technology.
From 1998- 2001 : Study in Le Hong Phong High School, Nam Dinh, in gifted class of computer studies
Job objectives:
Have an opportunity to work in a professional and active environment.
Find a challenging position that meets my capabilities, skills, education and experience to have a chance to prove myself.
Learn from experienced and talented colleagues.
Capacities:
Professional knowledge: good background of Printing, Information Technology.
Language skills: fluent at English.
Computer skills: good command of information technology, especially skilled in graphic software: Photoshop, Corel. Can use some office tools such as Word, Excel and PowerPoint.
Communication skills: open-minded, easy to make friend.
Have an inquiring min, always look for challenges, highly responsible.
Be willing to learn and work hard under great pressure and far from home.
Interest:
Like everything about Printing technology, graphic art.
Make friends
Read about science and economics
Explore the internet

It is acknowledged that all the information stated above is absolutely true and correct. For further information, I would be very pleased to be contacted at:

Who moved my cheese

(Who moved my cheese)-Dr Spence Johnson
Parts of All of Us
The Simple and The Complex
The four imaginary characters depicted in this story the mice: "Sniff" and "Scurry;' and the Little people: "Hem" and "Haw" are intended to represent the simple and the complex parts of ourselves, regardless of our age, gender, race or nationality.
Sometimes we may act like:
Sniff : Who sniffs out change early, or
Scurry: Who scurries into action, or
Hem :Who denies and resists change as he fears it will lead to something worse, or
Haw : Who learns to adapt in time when he sees changing can lead to something better!
Whatever parts of us we choose to use,we all share something in common:
a need to find our way in the Maze
and succeed in changing times.

Friday, February 22, 2008

Connect PHP and MySQL

Create file db_connect.php
db_connect.php content:
$host=localhost ;Mysql -server hostname
$user=root;// user privileges for mysql
$pass=password ;// User password
$port=3306;// Mysql port,common is 3306
mysql_connect($host,$user,$pass) or die ("could not connect to databases");
?>
And then,in other PHP file just add line
include("db_connect.php");

Thursday, February 21, 2008

Installling Apache PHP MySQL on Ubuntu

Install Apache and PHP 5

Apache HTTP Server

from terminal type:
sudo apt-get install apache2
start Apache server:
sudo /etc/init.d/apache2 start
from web browser type into adress bar: localhost

How to install PHP 5

sudo apt-get install php5
sudo apt-get install libapache2-mod-php5
sudo /etc/init.d/apache2 restart

To test if PHP 5 installed correctly
sudo gedit /var/www/testphp.php
insert following line :

save and exit.
from web browser type to adress bar: localhost/testphp.php 
If that didn't work, try these commands:
sudo a2enmod php5
sudo /etc/init.d/apache2 force-reload
(Optional) Install recommended PHP5 modules:
sudo apt-get install php5-xsl php5-gd php-pear
Restart Apache
sudo /etc/init.d/apache2 restart

The root directory of your web server is /var/www/ so you must
place your projects in this folder.


How to install MYSQL for Apache HTTP Server
sudo apt-get install mysql-server
gksudo gedit /etc/mysql/my.cnf
Find the line bind-address = 127.0.0.1 and comment it out
...
#bind-address           = 127.0.0.1
...
sudo /etc/init.d/mysql restart

sudo apt-get install libapache2-mod-auth-mysql
sudo apt-get install php5-mysql
sudo aptitude install phpmyadmin
gksudo gedit /etc/php/apache2/php.ini
You'll need to uncomment the ";extension=mysql.so" line so that
it looks like this
...
extension=mysql.so
...
from web browser type: http://localhost/phpmyadmin
 sources from http://ubuntuguide.org/wiki/Ubuntu

Installing Asterisk

Compiling Asterisk on most Linux distributions

Accomplish this by opening the folder in which the source codes were extracted (if you are using tarball files), or go to the /usr/src/asterisk folder (if using CVS server) to get the required packages.

To go to this directory, see example:

#cd /usr/src/asterisk

Once here, the final step is to compile:

Important: Follow this installation order: libpri, zaptel, asterisk

-Installing libpri

#cd /usr/src/asterisk/libpri
#make clean
#make
#make install

-Installing zaptel

#cd /usr/src/asterisk/zaptel
#make clean

Note: If you are using kernel 2.6 enter the following command '#make linux26', before doing '#make install'.

#make install

-Installing asterisk

#cd /usr/src/asterisk/asterisk
#make clean

Note: If you want to use a mp3 files for music-on-hold enter the following command '#make mpg123', before doing '#make install'.

#make install

If this is your first installation perform 'make samples' to install sample

(asteriskguru.com)

Fax Over IP (Part I)

Traditionally, there have been two approaches for sending FoIP networks:
real-time methods and store-and-forward methods. The primary difference in service between these two approaches lies in the delivery and method of receipt
confirmation. The Frame Relay Forum has defined a real-time protocol for the
transmission of fax-over–frame relay networks. Likewise, the ITU and Internet
Engineering Task Force (IETF) are working together to continue to evolve both
the real-time FoIP network standard (T.38) as well as the store-and-forward FoIP
network standard (T.37). Both T.37 and T.38 were approved by the ITU in June,
1998. Furthermore, T.38 is the fax transmission protocol selected for H.323.
There are tremendous opportunities for cost savings by transmitting fax calls
over packet networks. Fax data in its original form is digital. However, it is
modulated and converted to analog for transmission over the PSTN. This analog
form uses 64 kbps of bandwidth in both directions.
FoIP QoS
The advantages of reduced cost and bandwidth savings of carrying FoIP networks are associated with some QoS issues that are unique to packet networks and can affect the reliability of the fax transmission.
Timing
A major issue in the implementation of FoIP networks is the problem of
inaccurate timing of messages caused by delay through the network. The delay of fax packets through a packet network causes the precise timing that is required for many portions of the fax protocol to be skewed and can result in the loss of the call. The FoIP protocol in the IWF must compensate for the loss of a fixed timing of messages over the packet network so that the T.30 protocol operates without error.
There are two sources of delay in an end-to-end, FoIP call: network delay and
processing delay.
• network delay—This is caused by the physical medium and protocols
that are used to transmit the fax data and by buffers used to remove
packet jitter on the receiving end. This delay is a function of the
capacity of the links in the network and the processing that occurs as
the packets transit the network. The jitter buffers add delay when they
remove the packet-delay variation of each packet as it transits the
packet network. This delay can be a significant part of the overall delay,
as packet-delay variations can be as high as 70 to 100 milliseconds in
some frame-relay networks and even higher in IP networks.
• processing delay—This is caused by the process of demodulating and
collecting the digital fax information into a packet for transmission
over the packet network. The encoding delay is a function of both the
processor execution time and the amount of data collected before
sending a packet to the network. Low-speed data, for instance, is
usually sent out with a single byte per packet, as the time to collect a
byte of information at 300 bps is 30 milliseconds.
Jitter
Delay issues are compounded by the need to remove jitter, a variable interpacket timing caused by the network that a packet traverses. An approach to removing the jitter is to collect packets and hold them long enough so that the slowest packets to arrive are still in time to be played in the correct sequence. This approach, however, causes additional delay. In most FoIP protocols, a time stamp is incorporated in the packet to ensure that the information is played out at the proper instant.
Lost-Packet Compensation
Lost packets can be an even more severe problem, depending on the type of
packet network that is being used. In a VoIP application, the loss of packets can
be addressed by replaying last packets and other methods of interpolation. A
FoIP application, however, has more severe constraints on the loss of data, as the fax protocol can fail if information is lost. This problem varies, depending on the type of fax machine used and whether error-correction mode is enabled.
Two schemes that are used by FoIP software to address the problems of lost
frames are as follows:
• repeating information in subsequent frames so that the error can be
corrected by the receiver's playout mechanism
• using an error-correcting protocol such as TCP to transport the fax data
at the expense of added delay

Asterisk Hacking

Today,Asterisk become the most wide use solution for IP PBX.With Asterisk and one old PC ,you can building one system with many Application as:voicemail,Call forwarding,Music on hold,Call conferencing,v.vv.
So,you might be read this book,it;s truly useful for me when I'm development A NGN system called by Unified Messaging.I hope it can help you,too.Thank you.

Syngress Asterisk ...

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Tìm kiếm với Google

Thursday, February 28, 2008

Wednesday, February 27, 2008

How the Book is Organized

Part I. "Casing the Establishment"

Chapter 1. "Footprinting a VoIP Network"

Chapter 2. "Scanning a VoIP Network"

Chapter 3. "Enumerating a VoIP Network"

Part II. "'Exploiting the VoIP Network"

Chapter 4. "VoIP Network Infrastructure Denial of Service (DoS)"

Chapter 5. "VoIP Network Eavesdropping"

Chapter 6. "VoIP Interception and Modification"

Part III. "Exploiting Specific VoIP Platforms"

Chapter 7. "Cisco Unified CallManager"

Chapter 8. "Avaya Communication Manager"

Chapter 9. "Asterisk"

Chapter 10. "Emerging Softphone Technologies"

Part IV. "VoIP Session and Application Hacking"

Chapter 12. "Flood-Based Disruption of Service"

Chapter 13. "Signaling and Media Manipulation"

Part V. "Social Threats"

Chapter 14. "SPAM over Internet Telephony (SPIT)"

Chapter 15. "Voice Phishing"

Tuesday, February 26, 2008

Monday, February 25, 2008

Friday, February 22, 2008

Thursday, February 21, 2008

Apache HTTP Server

How to install PHP 5

How to install MYSQL for Apache HTTP Server

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Web2Phone

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Translation

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