tutorial 3 Flashcards
Which of the following describes the function of ARP?
A. It is used to map a 32-bit IP address to a 48-bit ethernet address.
B. It is used to map a 48-bit ethernet address to a 32-bit IP address.
C. It is used to map a 32-bit ethernet address to a 48-bit IP address.
D. It is used to map a 48-bit IP address to a 32-bit ethernet address.
It is used to map a 32-bit IP address to a 48-bit ethernet address.
ARP request is broadcast and ARP reply is _______.
a. broadcast
b. multicast
c. unicast
d. none of the above
c. unicast
Which of the following is the ethernet broadcast address used in ARP and RARP requests? A. 255.255.255.255 B. 08:00:20:11:aa:01 C. ff:ff:ff:ff:ff:ff D. 224.0.0.0
C. ff:ff:ff:ff:ff:ff
What is the purpose of the DHCP server?
A to provide storage for email
B to translate URLs to IP addresses
C to translate IPv4 addresses to MAC addresses
D to provide an IP configuration information to hosts
to provide an IP configuration information to hosts
What are the functions of The DHCP server?
A to provide storage for email
B to translate URLs to IP addresses
C to translate IPv4 addresses to MAC addresses
D to provide an IP configuration information to hosts
to provide an IP configuration information to hosts
During error reporting, ICMP always reports error messages to which node? a. Destination b. Source c. Next router d. Previous router
Source
Which of these is not a type of error-reporting message? A. Destination unreachable B. Source quench C. Router error D. Time exceeded
Router error
The TTL field has value 13. How many routers (max) can process this datagram? A. 11 B. 5 C. 10 D. 1
10
Explanation: ttl stands for time to live. This field specifies the life of the ip packet based on the number of hops it makes (number of routers it goes through). ttl field is decremented by one each time the datagram is processed by a router. when the value is 0, the packet is automatically destroyed.
The TTL field has value 13. How many routers (max) can process this datagram? A. 11 B. 5 C. 10 D. 1
10
Explanation: ttl stands for time to live. This field specifies the life of the ip packet based on the number of hops it makes (number of routers it goes through). ttl field is decremented by one each time the datagram is processed by a router. when the value is 0, the packet is automatically destroyed.
What should be the flag value M to indicate the last fragment?
a) 0
b) 1
c) TTl value
d) Protocol field value
0
Explanation: The Flag field in the IP header is used to control and identify the fragments. It contains three bits: reserved, don’t fragment and more fragments. If the more fragments bit is 0, it means that the fragment is the last fragment.
- Which field helps to check rearrangement of the fragments in IPv4?
a) offset
b) flag
c) ttl
d) identifer
Offset
The Fragment Offset field specifies where the fragment fits in the original datagram. The offset of the first fragment will always be 0. The size of the field (13 bits) is 3-bits shorter than the size of the total length field (16 bits).
If the value in protocol field is 2, which protocol should be used in IPv4
header?
.Which one fields of an IP header cannot be modified by a typical IP router? a. Checksum b. Source address c. Time To Live (TTL) d. Length
Source address
What is the size of the header checksum field in IPv4 header (in
bytes)?
16 bits
True
Name the fields that are related to fragmentation and reassembly of an IPv4 datagram? A. Identification B. Flags C. Fragment Offset field D. All of the above
All of the above
A router receives an IPv4 packet with the flag values D=0 and needs to do fragmentation because of smaller MTU on the outgoing
interface. What does the router do?
A. drop the packet if the Don’t Fragment (DF) flag bit is set in the packet’s header and send an Internet Control Message Protocol (ICMP) message which indicates the condition Fragmentation Needed
B. fragment the packet and send it over the link with a smaller MTU.
fragment the packet and send it over the link with a smaller MTU.
Explanation: if the value is 0 packet can be fragmented as necessary
What is The maximum number that IPv4 addresses can have?
32 bits or 2^32
while IPv6 has 128 bits
What are the limitations of IPv4 addresses?
a. The lack of address space (IP adress depletion)
b. Internet routing table expansion
c. Lack of end to end connectivity
d. Lack of quality of service support
e. all of the above
all of the above
Which of the following is incorrect about Network Address Translation
(NAT)?
A. NAT is a process in which one or more local IP address is translated into one or more Global IP address and vice versa.
B. NAT results in switching path delays.
C. Certain applications will not function while NAT is enabled
D. c
NAT results in switching path delays
What is the other name for Port Address Translation (PAT)?
a. porting
b. port overloading
c. port-level multiplexed NA
d. single address NAT.
e. all of the above
all of the above
In \_\_\_\_\_\_\_\_\_ type of NAT, one or more private IP addresses can be mapped to one public IP address. A. Static NAT B. Dynamic NAT C. PAT D. None of the above
PAT
Explanation
Port Address Translation (PAT) is an extension of Network Address Translation (NAT) that permits multiple devices on a LAN to be mapped to a single public IP address.
Which of the following is incorrect about NAT?
A. NAT does not conserve IPv4 addresses.
B. Static NAT creates a fixed translation of private addresses to public
addresses
C. Static NAT allows the user to configure one-to-one translations.
D. NAT helps to reuse private IP addresses
NAT does not conserve IPv4 addresses.
What is the fixed base header length of an IPv6 datagram?
a. 128 bits
b. 40 bytes
c. 40 bits
d. 128 bytes
b. 40 bytes
The traffic class field of IPv6 is similar to which field in the IPv4 header?
a. TOS field (Type of Service)
b. Fragment field
c. Fast Switching
d. Option field
TOS field
What are the type of addresses supported by IPv6?
a. Unicast
b. Anycast
c. Multicast
d. All of the above
All of the above
Which field determines the lifetime of IPv6 datagram?
a. Hop limit
b. TTL
c. Next header
d. None of the above
Hop limit
What is the size of an IP address in IPv6?
128bits
true
Which of the following is incorrect about IPv6 header format? A. Version field is of 4 bits. B. Flow Label field is of 20 bits. C. Next Header field is of 16 bits. D. Payload length field is of 16 bits
Next Header field is of 16 bits.
its supposed to be 8 bits
Which of the following is NOT correct about IPv6 address?
A. IPv6 supports real time applications.
B. IPv6 has increased address space when compared to IPv4.
C. IPv6 cannot be routed on IPv4 networks.
D. IPv6 has improved packet handling
IPv6 cannot be routed on IPv4 networks.
Which of the following is an incorrect IPv6 address?
A. 2001::1
B. FE80:0000:0000:0:0123:4567:89AB:CDEF:1010
C. 2003:DEAD:CAFE:cafe:ab33:46:abab:62
D. 2003:dead:bef:4dad:ab33:46:abab:62
FE80:0000:0000:0:0123:4567:89AB:CDEF:1010
Which of the following is an incorrect IPv6 address? A. FE80:FE80::1 B. 2001::CAFE C. 2001:0DB8::ABCD::1234 D. 2001:DB8:0:0:ABCD: :100
2001:0DB8::ABCD::1234
Functions/services offered by the network layer?
a. Logical addressing
b. Routing
c. only a is correct
d. both a and b are correct
Logical addressing and Routing
In __________ routing, the routing tables are updated periodically
and the routing tables are not manually updated by the network
administrator.
a. dynamic routing tables
b. datagram networks
dynamic routing tables
The Protocol Data Unit (PDU) for the application layer in the Internet stack is known as?
a. message
b. datagram
c. segment
d. frame
a. message
- PDU for physical layer is bits
- PDU for data link layer is frame
- PDU for network layer is packets
- PDU for transport layer is segments
Which protocol resolves the internet names?
Domain Name System (DNS)
True
Identify the correct order in which the following actions take place in
an interaction between a web browser and a web server.
1. The web browser requests a web page using HTTP.
2. The web browser establishes a TCP connection with the web server.
3. The web server sends the requested web page using HTTP.
4. The web browser resolves the domain name using DNS.
4, 2, 1 and 3
Which application-level protocol in which a manager control a set of agents? A. HTML B. TCP C. SNMP D. SCTP
correct = SNMP(Simple Network Management Protocol)
TCP stands for Transmission Control Protocol
SCTP (Stream Control Transmission Protocol)
Which of the following features has been enhanced in SNMPv3 when compared to SNMPv2? A. Management B. Integration C. Classification D. Security
D. Security
Which of the following is true about HTTP and HTTPS?
(i) HTTP is unsecured while HTTPS is secured.
(ii) HTTP sends data over port 80 while HTTPS uses port 443.
(iii) No SSL certificates are required for HTTP, with HTTPS it is required that we have an SSL certificate and it is signed by a Certificate Authority
(CA).
i, ii, iii all of them
List the E-mail protocols?
a. MTP (Simple Mail Transfer Protocol)
b. POP (Post Office Protocol)
c. IMAP (Internet Message Access Protocol).
d. all of the above
all of the above
Which transport layer protocol is used to support electronic mail? (A) SMTP (B) IP (C) TCP (D) UDP
TCP
The port numbers of the application layer protocols HTTP and HTTPS are ___80___ and
__443____respectively.
T/F
True
Define Cryptography in full.
Pain text - Encryption Algorithm - Transmission of cipher text - Decryption - Plain text
Consider different activities related to email: Identify the application level protocol used in each activity below?
m1: Send an email from a mail client to a mail server
m2: Download an email from mailbox server to a mail client
m3: Checking email in a web browser
m1 = SMTP(Simple Mail Transfer Protocol) m2 = POP(post office protocol) m3 = HTTP(Hypertext Transfer Protocol)
Which cryptographic type uses same key for encryption and decryption?
a. Symmetric cryptography
b. Asymmetric cryptography
Symmetric cryptography (same key) Asymmetric cryptography (unique keys)
Describe Ciphertext and Plaintext ?
Ciphertext - Encrypted text with a series of codes and symbols
Plaintext - Any text that is readable and understandable by humans
In security, CIA stands for
a. Central Intelligence Agency
b. confidentiality, integrity and availability
confidentiality, integrity and availability
List the private and public key encryption algorithms?
PRIVATE: DES, AES, RC4
PUBLIC: RSA, ECC, Deffie-hellman
An IP packet has arrived with the first few hexadecimal digits as shown below:
45000028000100000102 . . .
The data belong to what upper layer protocol?
How many hops can it travel before being dropped?
a) IGMP
b) UDP
c) OSPF
d) TCP
Answer: IGMP and 1 HOP
Explanation: TTL = 01, the packet can travel only one hop.
Protocol field = 02 means IGMP.
A packet has arrived in which the offset value is 100, the value of HLEN is 5 and the value of the total length field is 100. What is the number of the first byte?
a) 800
b) 880
c) 400
d) 780
Answer: 800
Explanation: Total data bytes = total length – header length = 80 bytes in this datagram.
First byte is 800.
In an IPv4 packet, the value of HLEN is 5, and the value of the total length field is 0x0028. How many bytes of data are being carried by this packet?
a) 10
b) 40
c) 60
d) 20
The HLEN value is 5, which means the total number of bytes in the header is 5 × 4, or 20 bytes (no options) The total length is 40 bytes, which means the packet is carrying 20 bytes of data (40 − 20).
An IP packet has arrived with the first 8 bits as 01000010. What is the version?
a) 3
b) 4
c) 5
d) 6
4
the first 4 bits show the version
