Archive for November, 2008

Been busy

Posted in General on November 20, 2008 by Xacker

It’s been a while since I wrote something, I have been busy. Sorry for that.

TCP/IP Suite

Posted in Networks on November 12, 2008 by Xacker

tcpip-suite

Encapsulation and De-encapsulation of packets

Posted in Networks on November 12, 2008 by Xacker

This tutorial has been written solely in Arabic, ofcourse, not on WordPress or I would have commited suicide, I hope this helps you more get to taste the sweet flavour of networks, I’m done with you ignoring my other network articles (mad)

😀

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The OSI Reference Model

Posted in Networks on November 10, 2008 by Xacker

The OSI Reference Model:
The early development of networks was chaotic in many ways. The early 1980s saw tremendous increases in the number and sizes of networks. As companies realized that they could save money and gain productivity by using networking technology, they added networks and expanded existing networks as rapidly as new network technologies and products were introduced.

By the mid 1980s, companies began to experience difficulties from all of the expansions they had made. It became more difficult for networks using different specifications and implementations to communicate with one another. The companies realized that they needed to move away from proprietary networking systems—those systems that are privately developed, owned and controlled. In a computer industry, “proprietary” is the opposite of “open“.

Proprietary means that one company or a small group of companies controls all use of the technology. Open means that use of the technology is available free to the public.

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Physical topologies of a network

Posted in Networks on November 9, 2008 by Xacker

following: Exploring the functions of a network

Physical topologies:

  • Bus topology: in a bus topology a cable proceeds from one computer to the next. The main cable segment must end with a terminator to absorb the signal when it reaches the end of the line or wire. If there is no terminator, the electrical signal representing the data bounces back at the end of the wire, causing errors in the network.
  • Star and Extended-Star topologies: the Star topology is the most common physical topology in Ethernet LANs. It is made up of a central connection point that is a device, such as a hub, switch, or router, where all the cabling segments actually meet. Each device on the network is connected to the central device with its own cable.
    Although a physical star topology costs more to implement than the physical bus topology, the advantages of a star topology make it worth the additional cost. Each device is connected to the central device with its own wire, so that if that cable has a problem, only that one device is affected, and the rest of the network remains operational. This benefit is extremely important and is the reason why almost every newly designed Ethernet LAN has a physical star topology.
    When a star network is expanded to include an additional network device that is connected to the main network devices, the topology is referred to as an extended-star topology. The problem with the pure extended-star topology is that if the central node point fails, large portions of the network can become isolated.
  • Ring and Dual-Ring topologies: unlike the physical bus topology, a ring type of topology has no beginning or end that needs to be terminated. Data is transmitted in a way that is very different from the logical bus topology. In one implementation, a “token” travels around the ring, stopping at each device. If a device wants to transmit data, it adds that data and the destination address to the token. The token then continues around the ring until it finds the destination device, which takes the data out of the token. The advantage of using this type of method is that there are no collisions of data packets, later I will explain what collisions in a network are.
    In a single ring topology, all the devices on the network share a single cable, and the data travels in one direction only. Each device waits its turn to send data over the network. The single ring, however, is susceptible to a single failure, stopping the entire ring from functioning.
    In a dual ring topology, two rings allow data to be sent in both directions. This setup creates redundancy (fault tolerance), meaning that if one ring fails, data can be transmitted on the other ring.
  • Mesh and Partial-Mesh topologies: another type of topologies that is similar to the bus topology is mesh topology (لو كانت مش طبولوجي تبقى ايه :P). The mesh topology connects all devices to one another for redundancy and fault tolerance. Implementing a full mesh topology is expensive and difficult. This method is the most resistant to failures, because any single link failing will not affect reach ability, why? You will understand that when I explain switching and interconnections.
    In a partial-mesh topology, at least one device maintains multiple connections to all other devices, without being fully meshed. This method reduces the cost of meshing all devices by allowing the network designer to choose which nodes are the most critical and appropriately interconnect them.

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No more Arabic text

Posted in General on November 9, 2008 by Xacker

Sorry guys but I have decided not to publish anything in Arabic unless it was some small text with no extensive formatting required, I have noticed that the look of my blog went buggy on both IE and FF not to mention that any edit to any arabic post will lead into aftermath disasters.

Thus I declare the Keylogger topic is suspended until revised again.

If you need a shoulder now I know just the right guy for that, Nour, go get him 😛

WPA Encryption No Longer Secure

Posted in Networks on November 8, 2008 by Sam

Security researchers Erik Tews and Martin Beck have succeeded in partially cracking the WPA (Wi-Fi Protected Access) encryption, which until now had been considered safe. The two hackers will demonstrate their feat at the upcoming PacSec security conference in Tokyo, Japan.

WPA is a protocol that has been widely adopted as a replacement for WEP (Wired Equivalent Privacy), which has been known to be insecure since as far back as 2001. The initial attack on WEP was actually a dictionary attack, thus requiring great computational resources. This meant that attack scenarios on a large scale were highly unlikely.
The uncertainty ended at the beginning of 2007, when Erik Tews, along with two student colleagues from the Darmstadt University of Technology in Germany, developed a new technique which allowed them to break WEP security in only two minutes. Their method, which became known as the PTW attack, prompted all security professionals to declare WEP a high security risk. In fact, the use of WEP as encryption protocol is what allowed hackers to steal millions of credit card details in the T.J. Maxx hit.

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And they say programmers don’t have sense of humor

Posted in General on November 7, 2008 by Xacker
We’ve designed Windows Live Hotmail storage to grow with you, but at a reasonable pace. That means you should have plenty of storage unless you suddenly want to store the planet Jupiter on Hotmail, in which case we’ll send you a nice e-mail asking you to please not try to store planets on Windows Live Hotmail (although gradual storage of moons and asteroids is ok).
a note at the footer of the page by Windows Live Hotmail website when you login with the new design.
and they say programmers don’t have any sense of humor 😀

Exploring the functions of a network

Posted in Networks on November 6, 2008 by Xacker

What is a network:

a bunch of connected devices and end systems, such as computers and servers, that can communicate with each other. Networks can be presented in different environments which can be categorized by the place where users exist, there are 4 major categories to where networks are implemented:

  • Main office: is a site where everyone is connected via a network and where the bulk of corporate information is located. It can have hundreds or even thousands of people who depend on network access to do their job. A main office may use several connected networks, which can span many floors in an office building or cover a campus that contains several buildings.
  • Remote locations:
    • Branch offices: smaller groups of people work and communicate with each other via a network. Although some corporate information may be stored at a branch office, it’s more likely that branch offices have local networks resources such as printers, but must access information directly from the main office.
    • Home offices: When individuals work from home, the location is called a home office. Home office workers often require on-demand connections to the main or branch offices to access information or use network resources such as file servers (where you store corporate or branch offices information and data, not like personal FTP servers).
    • Mobile users: mobile users connect to the main office network while at the main office, at the branch office, or traveling. The network access needs of mobile users is based on where the mobile users are located.

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How to tweak the output [CODE] for blogs

Posted in General on November 6, 2008 by Xacker

Following the topic: [CODE] Pimp your posts [/CODE]

How to tweak the output of Notepad++

After you have successfully edited your language styles through the /settings/styler configurator/ menu, you can export your code in HTML format as shown below:
Export from Notepad++
Of course you need the NppExport plug-in installed with Notepad++

Now that you have the HTML format, you can't just copy/paste the entire page code into you blog, why?
Speaking of wordpress.com, it doesn't support customized CSS (unless you upgrade) or embedded style sheets inside your topics, NppExport plug-in uses CSS to customize the appearance of each keyword, thus, copy/paste won't simply work because the embedded CSS will be removed on saving.

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