hiding ip address using anonymous proxy server

NOOR HAFIZAH CHE ALI - 2011110701

ITT730 ASSIGNMENT 2 Due: 3.00PM; 24 Mac 2012

Answer ALL Questions. (Submit your answers in a filename: A2-Your name to [email protected])

1. a) What is 11001010 in decimal?

202

b) Express the following IP address in binary: 128.171.17.13. (Hint: 128 is 10000000. Put

spaces between each group of 8 bits.)

10000000. 10101011. 00010001. 00001101

c) Convert the following address in binary to dotted decimal notation: 11110000 10101010

00001111 11100011. (Spaces are added between bytes to make reading easier.) (Hint:

11110000 is 240 in decimal.)

240.170.15.227

2. a) What kind of connection do you have at home?

Broadband

3. Go to the command line. Clear the screen. What kind of command do you get?

Microsoft Windows [Version 6.1.7601]

Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\HafizaH>

4. Use ipconfig/all or winipconfig.

a) What is your computer’s IP address?

183.78.19.149

b) What is its Ethernet address?

183.78.19.149

c) What is your default router (gateway)?

172.20.196.1


d) What are the IP addresses of your DNS hosts?

183.78.0.142

e) What is the IP address of your DHCP server?

172.20.196.1

f) When you get a dynamic IP address, you are given a lease specifying how long you may use

it. What is the starting time of your lease and the ending time?

Lease Obtained. . . . . . . . . . : Monday, March 19, 2012 9:55:47 PM

Lease Expires . . . . . . . . . . : Monday, March 19, 2012 11:25:47 PM

5. Ping a host whose name you know and that you use frequently. What is the latency? If this

process does not work because the host is behind a firewall, try pinging other hosts until you

succeed.

Approximate round trip times in milli-seconds:

Minimum = 72ms, Maximum = 81ms, Average = 75ms

6. Ping 127.0.0.1. Did it succeed?

Yes. It did.

7. Do a tracert on a host whose name you know and that you use frequently. You can stop the

tracert process by hitting Control-C.

a) What is the latency to the destination host?

98 ms

b) How many routers are there between you and the destination host? If this does not work

because the host is behind a firewall, try reaching other hosts until you succeed.

13

8. Distinguish between the information that ping provides and the data that tracert provides.


All 4 packets sent are received, then the connection is working fine. The first line is the

command I typed: ping www.google.com.my. The next line shows the full name of the

host, as found by the ping program. The number 209.85.175.94 is the IP address of the

host. The next four lines show whether or not the host replied, with how many bytes (size

of packet), round trip time (in milliseconds), and the TTL is how many routers the packet

will go through before giving up trying to find the host. The last lines show the statistics

from pinging the host. They include how many packets were sent, received, and lost. Also

shown are round trip times and averages

The first line is the command I typed: tracert www.google.com.my. The next line shows the

traceroute program acquiring the ip address from the domain. "Maximum of 30 hops" is

how many routers the packet will go through before giving up trying to find the host. The

next lines show each server the packets traveled through to get to the destination

www.google.com.my.These show both the IP address and domain name of the actual

servers that the packets passed through. Traceroutes can show where there is a break in

our connection. This allows us to determine exactly where our packets are being dropped

or lost. Dropped or lost packets on a traceroute will usually show as asterisks (*).

9. Find the IP address for Microsoft.com and Apple.com.

Host Name : Microsoft.com

IP Address : 207.46.232.182 and 207.46.197.32

Host Name : Apple.com

IP Address : 17.172.224.47 and 17.149.160.49

10. a) Look up RFC 1149. What kind of information do you get?

Standards Requests For Comment.A Standard for the Transmission of IP Datagrams on

Avian Carriers


b) In layperson’s terms, what does this RFC specify?

A document produced by the IETF that may become designated as an Official Internet

Protocol Standard. It specify on the needs for software and two hosts to communicate

c) What are its sections? (This is a serious question. You should learn how RFCs are

structured.)

STD, FYI and BCP

d) On what day was it created?

April 7, 1969

11. a) In telephony, what is a circuit?

� Circuits give reserved capacity to the other party for the duration of the call

◦ On every switch along the way

◦ On every line along the way

b) What two types of circuits can corporations use to link terminals with hosts?

Dial-up circuit

Leased line circuit

c) Compare and contrast these two types of circuits.

Dial-Up Circuit Leased Line Circuit

For homes and businesses For businesses

Can call anyone Point-to-point connection between two

sites

Reserved capacity for duration of a

call

Always on with reserved capacity

Low speeds for data (30 to 60 kbps) Speeds of megabits or gigabits per

second

Inexpensive Expensive

d) What is good about reserved capacity?

Reserved capacity is reasonably efficient for voice conversations

e) What is bad about reserved capacity?

Reserved capacity is inefficient (and therefore expensive) for data transmissions


f) What does it mean that data traffic is bursty?

Bursty traffic refers to an uneven pattern of data transmission: sometime very high data

transmission rate while other time it might be very low

g) Why is circuit switching very inefficient for bursty data traffic?

Circuit switching’s reserved capacity is inefficient (and therefore expensive) for data

transmissions, in which there are high-speed bursts separated by long silences in which

expensive reserved capacity goes unused.

12. a) In packet switching, what does the source host do?

Fragments the application message into many smaller pieces called packets

b) About how long is a packet?

100 bytes

c) Why is fragmentation done?

Easier for error correction. If there is an error transmission that destroy a packet, only the

lost packet needs to be resent.

d) Where is reassembly done?

At receiver

e) What is the benefit of multiplexing?

Save money by multiplexing multiple conversations over expensive circuits.

f) Why is packet switching good for bursty data traffic?

Packets of different conversations share the cost of trunk lines between packet switches.

This makes packet switching inexpensive and suitable for bursty data traffic

g) When a packet switch receives a packet, what decision does it make?

Go to the next switch

h) Do packet switches know a packet’s entire path through a network?

No


13. Why does it make sense to make only the transport layer reliable? This is not a simple

question.

Because transport layer usually is a fix up layer that supplies the functionality that the

internet layer lacks.

14. a) What does it mean that data transmission is bursty?

There are bursts of traffic followed by long silences.

b) Why is burstiness bad in circuit switching?

Burstiness is bad for circuit switching because circuit switching provides constant reserved

capacity, much of which will go unused with bursty transmission. The user has to pay for

reserved capacity whether or not it is used.

15. What layer fragments application messages so that each fragment can fit inside an individual

packet?

Transport layer

16. a) What device connects different networks into an internet?

Router

b) What is the old name for this device?

Gateways

17. a) Distinguish between internet with a lower-case i and Internet with an uppercase I.

◦ With an upper-case “I,” Internet means the global Internet we use every day.

◦ With a lower-case “i”, internet means any internet or the internet layer.

b) Why are many networking concepts duplicated in switched networks and internets?

Internetworking required adding a second layer of networking, duplicating concepts

but with different names.

c) What are the two levels of addresses?

48-bit MAC address

10-bit DLCI address


d) How long are IP addresses?

32 bits

e) How are IP addresses usually expressed for humans?

In dotted decimal notation. In this notation, the IP address broken into four 8-bit

segment.

f) Distinguish between packets and frames.

Packets Frames

A message at the internet layer A message at the data link layer

g) A host transmits a packet that travels through 47 networks. How many packets will there

be along the route?

1 packet

h) How many frames will there be along the route?

47 frames

i) Distinguish between switches and routers.

Switch Router

A device that forwards frames within a

single network

A device that forwards packets within an

internet. Routers connect two or more

single networks

j) Distinguish between physical links, data links, and routers.

Physical Link Data Link Router

A connection linking adjacent

devices on a network

The path that a frame takes

across a single network (LAN

or WAN)

A device that forwards

packets within an

internet. Routers

connect two or more

single networks.

k) Distinguish between what happens at the internet and transport layers.

Transport Layer Internet Layer

Packet assembly and assembly, error

correction, packet sequencing,

congestion control

Packet organization and forwarding


l) Why are application layer standards needed?

To communicate between applications

m) List the numbers and names of the five layers.

Number Layer

5 Application

4 Transport

3 Internet

2 Data Link

1 Physical

n) Are frames carried inside packets?

No, packet always travel inside frames

18. a) What are the roles of the Internet Protocol?

This layer deals with addresses, so addresses on an internet are called IP addresses

b) What are the roles of the Transmission Control Protocol?

◦ Provides transport layer functionality to fix problems

c) When would the User Datagram Protocol be used at the transport layer?

When applications do not need error correction or cannot wait for errors to be corrected.

Example: VoIP cannot wait for packet retransmission because voice must flow in real time.

Consequently, VoIP uses UDP at the transport layer instead of TCP.

19. What three networks were involved in the first test of the TCP/IP standards?

ARPANET, PRNET and SATNET

20. Both DHCP servers and DNS servers send a host an IP address. These are the IP addresses of

what hosts?

Originating host

GOOD LUCK!

hiding ip address using anonymous proxy server

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