uCertify Articles » IK0-002 http://www.ucertify.com/article Just another WordPress weblog Wed, 04 Nov 2009 00:00:00 +0000 http://wordpress.org/?v=2.8.4 en hourly 1 What is Trojan horse? http://www.ucertify.com/article/what-is-trojan-horse-2.html http://www.ucertify.com/article/what-is-trojan-horse-2.html#comments Wed, 19 Aug 2009 00:00:00 +0000 uCertify 1301109

Trojan horse is a malicious software program code that masquerades itself as a normal program. When a Trojan horse program is run, its hidden code runs to destroy or scramble data on the hard disk. An example of a Trojan horse is a program that masquerades as a computer logon to retrieve user names and password information. The developer of a Trojan horse can use this information later to gain unauthorized access to computers. Trojan horses are normally spread by e-mail attachments. Unlike viruses, Trojan horses do not replicate themselves but only destroy information on hard disks.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-trojan-horse-2.html/feed 0 Image Formats http://www.ucertify.com/article/image-formats.html http://www.ucertify.com/article/image-formats.html#comments Wed, 24 Jun 2009 00:00:00 +0000 uCertify 1301231

There are two basic methods for a computer to render or to store and display an image. When an image is saved in a specific format, it is created in either a raster or vector graphic format.

The Internet users are mostly familiar with raster images. A raster format breaks an image into pixels.

There are actually only two basic methods for a computer to render or to store and display an image. When an image is saved in a specific format, the image is created in either a raster or vector graphic format. The bits are used to create each pixel. The pixels denote the depth of color that can be put into the images. If the pixels are denoted with only one bit per pixel, then that pixel will be black or white. If the pixels are denoted with four bits-per-pixel, it means that a pixel can be set to 1 of 16 colors. Raster image formats can save at 16, 24, and 32 bits-per-pixel.

There are two common Internet image types in the raster format:

  • GIF
  • JPEG

Graphic Interchange Format (GIF) is the most common file format for images used on Web pages. The GIF format works well with line drawings, images with blocks of solid color, and pictures with sharp boundaries between colors. The GIF format has two versions, GIF89a and GIF87a. GIF89a allows users to save an animated GIF that is essentially a short sequence of images within a single GIF file, and supports transparency. GIF87a does not support animation and transparency. GIF stores 8 bits per pixel and is capable of displaying 256 colors.

Animated GIF files can be placed in an HTML page by using the <IMG> tag. Nearly all Web browsers support animated GIF files. These files are smaller than other animation files, such as Java applets.

Jpeg is a compression algorithm developed by the Joint Photographic Experts Group. Jpeg’s main feature is its compression factor that stores the image on the hard drive in less space than the image is when it actually displays. Although Jpeg reduces the file size of its normal size, some details are lost in the compression. Jpeg images support 16 million colors and are best suited for photographs and complex graphics such as trees, mountains, etc.

These are some of the other image types in the raster format:

  • TIFF
  • PCX
  • RLE (Run-Length Encoding)

Vector graphics formats offer advantages over traditional raster graphic formats such as GIF, JPEG, etc. Vector graphics files are much smaller in terms of the number of bytes they contain than bitmap files of the same objects with similar details. This makes Web pages load faster. Another asset of vector graphics is the fact that they can be easily scaled without loss of image resolution.

Vector graphics rendering is best suited to images in which shapes can be defined by mathematical functions. For example, straight lines, simple curves, waves, circles, ellipses, squares, rectangles, and triangles. In some situations, vector graphics are inferior to bitmap graphics. An example is a photograph of a complex nature scene including trees, clouds, and other objects with fractal features. While it is possible to render such images in vector format, the vector file may contain several times as many bytes as the equivalent bitmap file.

These are some of the image types in vector graphics format:

  • HDW (Harvard Draw)
  • GEM (Ventura Publisher)
Share/Bookmark]]> http://www.ucertify.com/article/image-formats.html/feed 0 What is Trojan horse? http://www.ucertify.com/article/what-is-trojan-horse.html http://www.ucertify.com/article/what-is-trojan-horse.html#comments Wed, 24 Jun 2009 00:00:00 +0000 uCertify 1301109

Trojan horse is a malicious software program code that masquerades itself as a normal program. When a Trojan horse program is run, its hidden code runs to destroy or scramble data on the hard disk. An example of a Trojan horse is a program that masquerades as a computer logon to retrieve user names and password information. The developer of a Trojan horse can use this information later to gain unauthorized access to computers. Trojan horses are normally spread by e-mail attachments. Unlike viruses, Trojan horses do not replicate themselves but only destroy information on hard disks.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-trojan-horse.html/feed 0 What is virus? http://www.ucertify.com/article/what-is-virus.html http://www.ucertify.com/article/what-is-virus.html#comments Sat, 20 Jun 2009 00:00:00 +0000 uCertify 1301230

A virus is a malicious program. A computer virus passes from one computer to another in the same way as a biological virus passes from one person to another. Most viruses are written with a malicious intent, so that they can cause damage to programs and data in addition to spreading themselves. Viruses infect existing programs to alter the behavior of programs, actively destroy data, and perform actions on storage devices that render their stored data inaccessible.

Computer viruses attack the software of a computer such as operating systems, data files, application software, and e-mails. However, viruses do not affect the computer hardware.

Viruses infect computers and spread themselves using various methods. Some viruses attach themselves to a common program such as a popular game or word processor. When a person downloads the infected game and runs it, the attached virus program gets executed. The virus then loads itself into memory and searches for any other program on the disk. If the virus finds any program, it modifies the program by adding the malicious code to the program. The next time this program gets executed, it infects other programs, and the cycle continues thereafter.

There are many types of computer viruses such as a boot-sector virus, macro virus, e-mail virus, etc.

A boot-sector virus infects the boot record on hard disks and floppy disks, which is used to start the computer. When the computer is turned on or restarted, the virus is automatically executed. An infected boot disk may stop the computer from starting up.

A macro virus is a macro or script that attaches itself to a file or template. When the file is loaded, the instructions of the macro or script are executed.

An e-mail virus moves around in e-mail messages, and usually replicates itself by automatically mailing itself to many people in the their e-mail address book.

Some other types of programs are also harmful to computers, which are not viruses such as a Trojan horse.

The main difference between a virus and a Trojan horse program is that a Trojan horse program does not replicate itself. A Trojan horse only destroys information on the hard disk. A Trojan horse program disguises itself as a legitimate program such as a game or utility. It often looks and initially acts in the same way as a legitimate program, but when it is executed, it destroys or corrupts data. A Trojan horse program can contain viruses, but it is not a virus itself.

A Worm uses computer networks and security holes to replicate itself. A Worm scans the network for another computer that has a specific security hole. It copies itself to the new computer using the security hole, and then starts replicating from there as well. A virus can have both virus and worm characteristics.

There are several anti-virus software programs that can detect, identify, and remove these viruses. As a precaution against viruses, we should take the following actions:

  • An anti-virus software program that can detect, identify, and remove viruses should be installed on the computer.
  • All information downloaded from the Internet or some unknown resource must be immediately scanned for viruses by using an anti-virus software.
  • Any e-mail attachment that comes from unknown sources should never be opened.
Share/Bookmark]]> http://www.ucertify.com/article/what-is-virus.html/feed 0 What is DMZ? http://www.ucertify.com/article/what-is-dmz.html http://www.ucertify.com/article/what-is-dmz.html#comments Sat, 20 Jun 2009 00:00:00 +0000 uCertify 2200

Demilitarized zone (DMZ) or perimeter network is a small network that lies in between the Internet and a private network. It is the boundary between the Internet and an internal network, usually a combination of firewalls and bastion hosts that are gateways between inside networks and outside networks. DMZ provides a large enterprise network or corporate network the ability to use the Internet while still maintaining its security.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-dmz.html/feed 0 Skills required for CIK-002. http://www.ucertify.com/article/skills-required-for-cik-002.html http://www.ucertify.com/article/skills-required-for-cik-002.html#comments Fri, 19 Jun 2009 00:00:00 +0000 uCertify 1301143

CompTIA has specified more than thirty objectives for the CIK-002 test, which are grouped under four topics. Following are some important areas in which an individual should possess good knowledge before taking the CIK-002 test:

  1. Identifying the issues that affect Internet site functionality, performance and security.
  2. Understanding the concept of caching and its implications.
  3. Using different types of search indexes – static index/site map, keyword index, full text index.
  4. Describing the infrastructure needed to support an Internet client and update client software.
  5. Administration of Internet/intranet sites.
  6. Understanding programming-related terms and differences between popular client-side and server-side programming languages.
  7. Creating HTML pages, use of various multimedia extensions or plug-ins, and use of various image and multimedia file formats.
  8. Identifying the common formats used to deliver content to wireless devices, and use of popular tools to connect a Web server to a database.
  9. Testing pre-production Web and e-commerce servers.
  10. Describing the core components of the Internet infrastructure, and use of Internet domain names and DNS.
  11. Describing the capabilities of popular remote access protocols, and how various protocols or services apply to the function of their corresponding server, such as a mail server, a Web server or a file transfer server.
  12. Identifying when to use various diagnostic tools for resolving Internet problems.
  13. Understanding when to use various site monitoring procedures.
  14. Understanding how common networking topologies are used.
  15. Understanding various Internet security concepts and identifying suspicious network activities.
  16. Identifying appropriate access-control security features for an Internet server.
  17. Describing the uses and proper instances to use anti-virus software.
  18. Describing how firewalls are used to protect private networks, and using various DMZ configurations.
  19. Describing various authentication/encryption technologies, e-commerce terms, and concepts.
  20. Explaining the current types of e-business models being applied today.
  21. Identifying key factors relating to strategic marketing considerations as they relate to launching an e-business initiative, and key factors relating to legal and regulatory considerations when planning e-business solutions.
Download free practice test for i-net-plus I-Net+ exam. Best exam simulation CompTIA IK0-002 download free trial. Share/Bookmark]]> http://www.ucertify.com/article/skills-required-for-cik-002.html/feed 0 What is SSL? http://www.ucertify.com/article/what-is-ssl.html http://www.ucertify.com/article/what-is-ssl.html#comments Tue, 16 Jun 2009 00:00:00 +0000 uCertify 454

Secure Sockets Layer (SSL) is a protocol used to transmit private documents via the Internet. SSL uses a combination of public key and symmetric encryption to provide communication privacy, authentication, and message integrity. Using the SSL protocol, clients and servers can communicate in a way that prevents eavesdropping and tampering of data on the Internet. Many Web sites use the SSL protocol to obtain confidential user information, such as credit card numbers. By convention, URLs that require an SSL connection start with https: instead of http:. By default, SSL uses port 443 for secured communication.

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The IP address 127.0.0.1 is known as the loopback address for a computer. This address is used with the PING command to test TCP/IP on a computer. It uses a loopback driver to reroute the outgoing packets back to the source computer.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-loopback-address.html/feed 0 What is Digest authentication? http://www.ucertify.com/article/what-is-digest-authentication.html http://www.ucertify.com/article/what-is-digest-authentication.html#comments Sun, 17 Jun 2007 00:00:00 +0000 uCertify 1301097

Digest authentication is a secure authentication method in which passwords are sent across a network as a hash value rather than as clear text. It is a more secure authentication method as compared to Basic authentication. Digest authentication works across proxy servers and firewalls.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-digest-authentication.html/feed 0 What is Integrated Windows authentication? http://www.ucertify.com/article/what-is-integrated-windows-authentication.html http://www.ucertify.com/article/what-is-integrated-windows-authentication.html#comments Sun, 17 Jun 2007 00:00:00 +0000 uCertify 1301098

Integrated Windows authentication is a method of authentication that uses the security features of Windows clients and servers. It is more secure than Basic or Digest authentication. Integrated Windows authentication relies on Internet Explorer and does not work over HTTP proxies. Therefore, it is best for use in intranets where all the clients are within a single domain.

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