Computer Network Security

The computer network security is a key issue to promote the development of trade in all areas. One word ‘security’ covers many different aspects, both technical, organizational and legal. Latitude users against security problems is often irrational, which does not help to simplify the discussion. The safety of paying by credit card over the Internet is part of controversial topics. In 1996 our experimental platform Infoway, we asked our 10,000 users to pay a participation fee for access. All means of payment were available on the server from the secure online credit card, send the card number by fax or check. Contrary to popular belief, approximately 60% of users chose the secure online payment, 30% and 10% check preferred to send the credit card number by fax which even provided a PIN! The perception of safety is an important element to consider in developing these systems.

From a technical perspective, safety covers both access to information on workstations, servers and network data transport. In this short paper, we focus on the problems of information security in trade through public or private networks. Internet, the network of networks, is a tool that allows all computers regardless of their type to communicate with each other. Technology (TCP / IP) has simplified the creation of networks, thus reducing the cost of telecommunications. However, the security features are not addressed by this protocol.

Giant Microsoft Will Buy the Phone Service Skype f...

Software giant Microsoft has announced today that it agreed to buy the online telephony service Skype for $ 8.5 billion $ U.S., its largest acquisition in 36 years of history.

The acquisition of Skype would offer Microsoft a potentially valuable tool for communication while the firm tries to increase its presence on the Internet and the smart phone market.

Skype is particularly held by the website and eBay auction fund Silver Lake. The service has 663 million users worldwide.

Microsoft wants to marry the functions of Skype with its Xbox game console, the mail program Outlook and Windows smartphones.

About 170 million people use Skype’s services each month. They spent over 207 billion minutes of voice and video communications in 2010.

Entrepreneurs Niklas Zennstrom and Janus Friis, who started the company in 2003, have struggled to make their business profitable since most people use Skype calling services for free. Approximately 8.8 million customers per month, only 5 percent of the total number of users pay for services.

The group would have lost $ 7 million last year for a turnover of U.S. $ 860 million. End of 2010, its long-term debt was U.S. $ 544 million.

The current CEO of Skype Tony Bates retain the head of the company.

Microsoft makes its biggest acquisition so, after the takeover in 2007 of technology providers for digital marketing Aquantive approximately U.S. $ 6 billion.

The site eBay acquired Skype in 2005 for U.S. $ 2.6 billion, but he never managed to combine phone service and bids.

He had sold 70 percent of its shares to an investor group led by Silver Lake funds Horowitz and Andreessen to U.S. $ 2 billion 18 months ago.

Wi-Fi Is It Dangerous to The Health of Children?

This topic is not directly subject to the site. However, I am asked more often the question: Wi-Fi or mobile phone are dangerous to health especially children?

So I decided to address this issue by providing the scientific facts that will help you form an opinion. It is impossible to prove that a particular product is not dangerous. However, it is possible to measure the effects and to deduce levels of risk.

The common feature of Wi-Fi or mobile phone is to receive and emit radio waves. This is not new since radio, television and most telecommunications systems use these waves for a hundred years. What is new is the proliferation of these devices that are installed by tens of millions of users nearby. To assess the level of dangerousness, we must understand the nature of radio waves or radio frequency (RF) and their action on the human body.

Small breviary radio waves or radio frequency (RF)

Radio waves or radio frequency (RF) are created by the movement of electrical charges in antennas. These waves consist of an electric field and magnetic fields that radiate into space from the antenna. Their propagation speed is the speed of light. What differentiates the waves is their frequency-the number of cycles per second wave-which we can deduce the wavelength of the light-speed divided by frequency, which is the distance traveled by a wave. Frequency expressed in Hz (hertz), kHz, MHz (1 million) or GHz (one billion). To give current values, the frequencies of FM radio stations are between 88 and 108 MHz, television between 300 and 600 MHz, the mobile phone 900 or 1800 MHz and 2400 MHz Wi-Fi (2.4GHz).

Intranet: For What Services?

The introduction of the Intranet within the company allows both to install new applications quickly and increase the capabilities of existing applications by making them communicate. The new possibilities offered by the intranet within the company are many. Improving communication, the sharing of geographically dispersed resources to accomplish a task, the possibility of combining both a local presence by taking advantage of access to global expertise of the company, the creation of virtual teams without increasing overheads, the ability to provide service 24 hours a day 24 a new beginning each time in the world.

The first services to implement an Intranet are naturally those who have made the success of the public Internet and the first email. A recent survey by Gartner Group survey of 500 companies provided the top 5 applications Intranet:

1. Email
2. Access to public Internet
3. Access to corporate data
4. The distribution and publication of information
5. Records management.

The installation of an e-mail or connecting the local mail with the rest of the world via the Internet is the operation priority. The savings are immediate. An electronic message is from three to ten times cheaper than a fax in the distance. Its asynchronous nature, email adapts to jetlag. Attachments of all types reduce photocopying and allow modification and reuse of materials. One constraint: it must be used personally.

The establishment of an intranet with email is inseparable from the constitution and the provision of all a business directory that maintains information about employees, services or applications available and the controls of access. Such directory services are available on the network. Users will find information such as phone numbers and email addresses. Administrators manage access to services, applications also have direct access to this information. These directories, when they existed, were closed and proprietary. A recent standard (LDAP) directory will allow them to communicate and to exchange electronic business cards.

Understanding IPv6

An IPv6 address is much longer than IPv4 address. This is one reason to use the new protocol. The number of addresses is virtually infinite. Each machine (node ​​in IPv6 terminology) connected to the network can use a global IPv6 address or addresses. No more complications NAT and port forwarding. Again all the machines can communicate directly.

An IPv6 address is represented by 128 bits (32 in IPv4) that is written in 8 suites with 4 hexadecimal characters (0-9, af) separated by colons:

2a01: 05d8: 52eb: be1d: F053: 2abf: ef7d: 6c89

The notation of IPv6 addresses

The notation has 39 characters. It can be simplified by removing the leading zeros and replacing a sequence of zero. The following addresses are all equivalent.

2001:0 db8: ab 0000:0000:0000:0000:1428:57
2001:0 db8: 0000:0000:0000:: 1428:57 ab
2001:0 db8: ab 0:0:0:0:1428:57
2001:0 db8: 0:0:: 1428:57 ab
2001:0 db8:: 1428:57 ab
2001: db8:: 1428:57 ab

Addresses 2001: db8:: / 32 as above are used for examples and are not routed.
URL notation

IPv6 addresses in URLs are written in [] that adds a port number if necessary.

http:// [2a01: 5d8: 52eb: be1d: F053: 2abf: ef7d: 6c89]: 81 /

Scoring Network

This is the CIDR format that is used in IPv6. It shows the number of bits that are identical in all places of the network. Example
2a01: 5d8: 52eb:: / 48 represents the network address range from which
2a01: 5d8: 52eb: 0:0:0:0:0 to
2a01: 5d8: 52eb: ffff: ffff: ffff: ffff: ffff

This is different from the concept of class used in IPv4. The goal is to simplify the routing tables.

Should We Move to IPv6 Now?

A short guide to understanding IPv6

Since January 2008 Free has deployed IPv6 in its offer public. It is the culmination of a long walk. The project IPv6 [Internet Protocol version 6] was launched in 1990 and adopted as standard by the IETF to replace IPv4 in 1998.

Today the Internet works primarily with the IPv4 protocol, which has more than twenty years of age. IPv4 has the fantastic growth of the Internet with a few modifications like NAT. In 2008, the 4 billion of public IPv4 addresses are nearly all attributed as the number of devices connected to the Internet in particular mobile phones is growing strongly. The transition to IPv6 that provides virtually unlimited address space (1038) is inevitable. IPv6 also brings benefits such as improved routing performance and simplifying the auto network configuration. However, IPv6 is not compatible with IPv4. He has to manage a transition, which is never easy. The aim of this paper is to serve as a practical guide to become familiar with IPv6 at home, not to replace the reference document or external website to thousands of articles that detail the characteristics of this protocol.

How to switch to IPv6 at home

You need a Free unbundled access. In the management interface of the Freebox, check IPv6 Support and restart the Freebox.

If you have an Ubuntu Linux machine, there is nothing to do. IPv6 is enabled by default.  Windows XP SP2, you must first install protocol “Microsoft TCP / IP version 6″ over the “Internet Protocol (TCP / IP) that supports IPv4 (type ipv6 install in a command window).
Windows Vista, IPv6 is enabled by default.

IPv6 addresses are assigned automatically. In fact, you keep your IPv4 addresses that coexist side by side, with IPv6 addresses.

IP Telephony, How Does It Work?

First a brief return to traditional telephony. The positions of traditional phones are connected directly to the public for private branch exchanges or PBXs through in business. It provides for the exchange line during the unit’s power. The transmitted signal is an analog signal.

The public switches are interconnected by specialized networks for voice transmission. The telephone number corresponds physically to a telephone line on the switch designated. To make a call, it is necessary to establish a connection, a circuit between the calling line and the line drawn through these exchanges. Fifty years ago, these switches were made with extraordinarily large complex electromechanical systems. It had huge rooms to install them. In the early 1970s, these systems have gradually been replaced by computers. The size and price of the systems decreased significantly, but the telecoms engineers have questioned the system architecture which has remained the same. Most technical advances have been made between the PBX, the interface of the subscriber line remained the same.

IP telephony is a set of telephone functions using the IP to transmit voice and manage phone functions. voice, digitized and compressed, is transmitted as packets routed in the same manner as data packets. So there is more switching circuits is the standard feature of Internet routing is used.

Netmeeting was one of the first applications to transmit voice over IP. He had a PC connected to the Internet to digitize voice and send it. The result was not famous. The sound settings were delicate and the latency (time forwarding packets) added to the time compression of voice, did not allow a natural conversation. With the advent of ADSL and computers 20 times faster, the situation has changed. Skype, released in September 2003, was the first VoIP software to make usable. The system is owned and unfortunately his phone features are limited. It does so between 2 PCs equipped with Skype. In early 2004, Skype has introduced the function and conference since July 2004, Skype offers a paid service to call or be called by landlines.

To aspire to replace fixed telephony, it takes a whole lot more advanced features. NetMeeting uses the H.323 standard developed by ITU-T, who copied the principles of traditional telephony.
A new protocol, much better suited to the Internet was developed by the IETF SIP. It is this protocol that will enable the development of telephony features. It also helps develop “SIP phones” that allow you to connect directly to the Internet by way of PC.

A PC In Your Pocket or How Many Use The Mobile Int...

It is now possible to work in the street with a mobile phone almost like home or office with a PC. You can use these new mobile phones called smartphones without paying much, without managing duplicated emails, contacts, calendar etc. .. or without synchronizing data with a still camera.

The aim of this paper is to first provide some guiding principles to use and very practical advice to make best use these new phones.

The mobile phone: how does it work?

I started with a mobile phone in 1985 with the analog system Radiocomm 2000. It was a classic radio transceiver. The voice quality was very poor, the time of establishment of a communication very long, expensive pricing. The number of users was limited by a small number of frequencies available.

Digital mobile telephony began in the early 1990s in Europe with the advent of GSM (Global System for Mobile). The system transmits voice and text messages (SMS) to digital. The sound quality has become convenient. The set-up is a few seconds. The problem has been fixed frequency by the juxtaposition of cells of varying sizes that allow hundreds of simultaneous calls per cell. The price of equipment has become very cheap as and when increasing the number of units sold. It remains the cost of communications, still too high in France because of an oligopoly. The arrival in early 2010 for Free in this landscape will perhaps shake the status quo.

The deployment of the Internet has led to a request for access by mobile phones, not just to provide the necessary speed, the voice channel is limited to ten kbps We remember the flop of WAP and dashed hopes to UMTS. Today most “Smartphones” are compatible GSM, GPRS (30-40 kbps), EDGE (80-115 kbps) and HSDPA (7.2 Mbit / s downstream and 128Kbit / s upstream) . The type of active connection (switching is automatic) is usually indicated on your phone (E for EDGE, HSDPA H, etc. ..) and varies depending on where you are. In addition to these mobile networks, your phone can connect to the Internet via Wi-Fi and has a Bluetooth wireless connection to connect to a headset or stationary equipment such as a PC. It is also generally possible to connect via USB to a PC to exchange files or recharge the battery.