IT430 Final Term Subjective Questions

Q17. What is the function of UDP protocol at TCP/IP stack? Give precise answer.

Q18. What tag is used for displaying a border between the frames? (1 marks)

BORDER or FRAMEBORDER – Set this attribute to 0 for not displaying a border between the frames

Q19. Suppose there is an applet at " Write the code to (2 marks)

<HTML> <BODY>

</BODY> </HTML>

Q20. Identify the object, property and method in the following:

Math.sin(45) Math.PI

Answer: Math is the object in above case PI is the property of Math object Sin () is the method of Math object

Q21. What is a web form? What is its usage in reference to client-server communication? 2+3

A web form on a web page allows a user to enter data that is sent to a server for processing. Web forms resemble paper forms because internet users fill out the forms using checkboxes, radio buttons, or text fields. For example, web forms can be used to enter shipping or credit card data to order a product or can be used to retrieve data

Forms can be combined with various scripting languages to allow developers to create dynamic web sites. This includes both client-side and/or server-side languages.

The de facto standard client-side scripting language for web sites is JavaScript. Utilizing JavaScript on the Document Object Model (DOM) leads to the method of Dynamic HTML that allows dynamic creation and modification of a web page within the browser. While client-side languages used in conjunction with forms are limited, they often can serve to do pre-validation of the form data and/or to prepare the form data to send to a server-side program.

Q22. Explain the following frame tags? Discuss the usage of these (10 marks)

1. <frameset>
2. <frame>
3. <Noframes>
4. <Iframe>

<frameset>…</frameset>

Contains the frameset The frames layout is given by comma separated lists in the rows and cols attributes.

<frame> or <frame/>

Delimits a single frame, or region, within the frameset A separate document linked with the src attribute appears inside.

<noframes>…</noframes>

Contains normal HTML content for user agents that don't support frames

<iframe>…</iframe>

An inline frame places another HTML document in a frame. Unlike an object element, an inline frame can be the "target" frame for links defined by other elements and it can be selected by the user agent as the focus for printing, viewing its source etc.

Q18. What it stands for IIS? (1 marks)

IIS (Internet Information Server)

Q19. When does we use the parseFloat() function?

„Parse Float (string)‟ parses the string as a floating point number, is the example of a function/method of Global Object.

Q20. Name the JavaScript function that convert strings to float numbers. How do you give the function a string value to convert to a number? (3 marks)

JavaScript provides two functions to convert this string value to a numeric data type;

parseInt

and

parse

Float(). By using parse float function we can convert strings to float numbers. To convert string to integer we can use parseInt function. Using this function we can only convert string numbers to numeric data but alphabetic characters we can't convert.

Q21. Write your personal profile in a file saving it with the extension of e.g. “abc.js”and then call it in a JavaScript code.

Q22. Explain any three of the outside attacks briefly. (10 marks)

Out side attacks on a network

1. Eavesdropping/ sniffing/snooping

In this type of attack the hacker has the ability to monitor network traffic using some kind of network monitoring software. For example, a hacker may install some backdoor or Trojan horse that can monitor the key strokes of a user while typing and send the typed information to the hacker.

2. Password attacks

Such attacks are basically a result of eavesdropping through which the hacker is able to know the account ID or password of a particular user. Then using it the hacker gains access to the network and gather information such as user names, passwords, computer names, resources etc. That can lead to modification, deletion or rerouting of network data.

3. IP address spoofing

You know that there are two IP addresses available on a data packet – IP addresses of the sender and the destination. The address of the destination only matters for routing. It is possible that a hacker (having special capabilities) seizes the control of a router, changes the IP address of the source/sender on data packets and thus forces the destination machine to send the information/web page to a different machine, that is, the machine of the hacker. This is called IP address spoofing.

4. Man in the middle attacks

In it the attacker is able to monitor, capture and control data between sending and receiving machines. He may apply IP address spoofing technique to divert the packets to its machine, then modify the packets and resend the misleading