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IPV4 Addressing

Subject : it-skills

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Disables the sending of ICMP redirect messages
IANA
Don't Fragment
Host-to-host
Router(config-if)#no ip redirects

2. What is the format of the TCP Header Length field?
Length of header in words (32-bit)
Router#clear arp-cache [{interface {interface}} | {ip-address}]
Internet
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111

3. Who is responsible for maintaining the official assignments of TCP and UDP port numbers for specific uses?
Router(config-if)#no ip proxy-arp
IANA
Each router decrements the TTL
255.255.255.128

4. Which IPv4 address range is reserved for link-local addresses when DHCP fails?
255.255.255.128
Socket
4
169.254.0.0/16

5. What is ICMP Type 5?
Regional Internet Registry
255.255.255.224
Redirect
Router Selection

6. What is ICMP Type 3?
Open Systems Interconnection
0.0.0.0/8
Internet Corporation for Assigned Network Numbers
Destination Unreachable

7. What routing protocols are classful?
192.88.99.0/24
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Source Port (16-bit); Destination Port (16-bit); Sequence Number (32-bit); Acknowledgement Number (32-bit); Header Length (4-bit); Reserved (4-bit); Flags (8-bit); Windows Size (16-bit); Checksum (16-bit); Urgent Pointer (16-bit); Options; Padding
RIPv1 and IGRP

8. What is prefix /26 in decimal notation?
8
Urgent
RIRs
255.255.255.192

9. What is CWR?
Don't Fragment
Router(config-if)#arp timeout {seconds}
8
Congestion Window Reduced

10. What is the difference between the ToS and the DiffServ byte?
They are the same byte - but the names and value interpretations are different
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)
46
Router(config-if)#no ip proxy-arp

11. What is SYN?
6
Number of octets to be added to the Sequence Number to indicate the end of the urgent data
Synchronize
Application

12. What is the content of the Maximum Segment Size (MSS) in the Option field of the TCP header?
An ARP request issued by a host with its own IPv4 address as the target address
Largest segment size that the sender is willing to accept
RFC 791
255.255.255.128

13. What TCP/IP protocol suite layer corresponds to the transport layer of the OSI model?
Version (4-bit); Header Length (4-bit); ToS (8-bit); Total Length (16-bit); Identifier (16-bit); Flags (3-bit); Fragment Offset (13-bit); TTL (8-bit); Protocol (8-bit); Header Checksum (16-bit); Source Address (32-bit); Destination Address (32-bit);
Host-to-host
1
IPv4 and IPv6

14. What is the ARP Operation value for a Reverse ARP Request?
Regional Internet Registry
3
Identifier; Flags and Fragmentation Offset
RFC 3330

15. What is the format of an ARP packet?
169.254.0.0/16
Protocols that include subnet masks in their routing updates
Hardware type (16-bit); Protocol type (16-bit); Hardware address length (8-bit); Protocol address length (8-bit); Operation (16-bit); Sender hardware address; Sender protocol address; Target hardware address; Target protocol address
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16

16. Who owns the processes by which public IP address space and AS numbers are allocated and assigned?
Reset
ICANN
255.255.255.240
60 octets

17. Who allocates public IP address ranges to NIRs or LIRs?
Acknowledgements - checksums and timers
RIRs
Echo
Number of octets to be added to the Sequence Number to indicate the end of the urgent data

18. Who administers and registers public IP address space and AS numbers within a country or economic unit?
255.255.255.224
NIRs
Internet Protocol
Mostly large ISPs - enterprises - or academic institutions

19. What is ACK?
Router Selection
Acknowledgement
Router(config)#ip arp proxy disable
Identifier; Flags and Fragmentation Offset

20. What is the ARP Hardware type value for Ethernet?
4
1
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
Used by a host to obtain the IP address associated with another host's MAC address

21. What is the content of the TCP Window Size field?
All Internet Registries
Number of octets - starting with the octet indicated by the Acknowledgement Number - that the receiver will accept from the sender before the sender must stop transmitting and wait for a new Acknowledgement
Regional Internet Registry
2

22. Who allocates IP address space and AS numbers to RIRs?
An ARP request issued by a host with its own IPv4 address as the target address
IANA
DHCP
Data Offset

23. What is covered by the TCP Checksum field?
Local Internet Registry
Both the TCP header and the encapsulated data
4
3

24. What TCP/IP protocol suite layer corresponds to the physical and data link layers of the OSI model?
Network interface
60 octets
17
Mostly large ISPs - enterprises - or academic institutions

25. What is the minimum length of an IPv4 header?
20 octets
192.0.2.0/24
198.18.0.0/15
Maximum Segment Size (MSS)

26. What are the protocol categories that describe the physical layer?
Mostly large ISPs - enterprises - or academic institutions
Sequence Numbers
Electrical/Optical - Mechanical - Functional and Procedural
Padding of zeros to ensure that the header ends on a 32-bit boundary

27. What is prefix /27 in decimal notation?
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111
Largest segment size that the sender is willing to accept
Loose source routing; Strict source routing; Record route; Timestamp
255.255.255.224

28. Which RFC defines IPv4?
4
Echo
Padding of zeros to ensure that the header ends on a 32-bit boundary
RFC 791

29. What is the IPv4 protocol number for UDP?
Loose source routing; Strict source routing; Record route; Timestamp
National Internet Registry
Hardware type (16-bit); Protocol type (16-bit); Hardware address length (8-bit); Protocol address length (8-bit); Operation (16-bit); Sender hardware address; Sender protocol address; Target hardware address; Target protocol address
17

30. What is prefix /30 in decimal notation?
LIRs
URG flag set
ICMP Router Discovery Protocol
255.255.255.252

31. What is IANA?
Protocols that don't include subnet masks in their routing updates
Internet Assigned Numbers Authority
Used by IRDP on some operating systems to discover local routers
8

32. What is IRDP?
0.0.0.0/8
127.0.0.0/8
ICMP Router Discovery Protocol
National Internet Registry

33. Which IPv4 address range is reserved for IPv6 to IPv4 (6to4) relays (RFC 3068)?
192.88.99.0/24
Application
Internet Corporation for Assigned Network Numbers
192.0.2.0/24

34. What is the formula to calculate the next Sequence Number based on the Sequence Number of the current TCP segment?
ICANN and IANA
Sequence Number + Data payload octets + 1
169.254.0.0/16
LIRs

35. Which IPv4 address range is reserved for self-identification on a local subnet?
RFC 1918
Acknowledgement
Protocols that don't include subnet masks in their routing updates
0.0.0.0/8

36. What is the format of the Flags field in the TCP header?
Method where routers - by responding to ARP requests for IP addresses in different subnets - make themselves available to hosts with no default gateway configured
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
Router(config-if)#arp timeout {seconds}
Time to Live

37. What is the maximum length of an IPv4 header?
60 octets
Router Selection
Windowing
Address Resolution Protocol

38. What is the first octet rule for IPv4 address classes in binary?
Protocols that don't include subnet masks in their routing updates
They are the same byte - but the names and value interpretations are different
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111
Padding of zeros to ensure that the header ends on a 32-bit boundary

39. Who assigns IP address space to its own customers?
Electrical/Optical - Mechanical - Functional and Procedural
3
Protocols that include subnet masks in their routing updates
LIRs

40. What is IP?
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
National Internet Registry
Internet Protocol
Reserved (1-bit); DF (1-bit); MF (1-bit)

41. What TCP/IP protocol suite layer corresponds to the network layer of the OSI model?
Padding of zeros to ensure that the header ends on a 32-bit boundary
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
Internet
Subtract Header Length field from Total Length field

42. How can the receiver determine the size of a packet's data payload based on the IPv4 header?
Subtract Header Length field from Total Length field
Number of octets to be added to the Sequence Number to indicate the end of the urgent data
0
255.255.255.240

43. Who can assign IP address space to end user organizations?
Internet Assigned Numbers Authority
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254
0
All Internet Registries

44. What is prefix /25 in decimal notation?
1 Determine how many subnets are required; 2 Determine how many hosts per subnet are required; 3 Determine the subnet mask for each subnet; 4 Calculate the network address for each subnet
Router#debug arp
255.255.255.128
Internet Service Provider

45. What is TCP?
More Fragments follow
Don't Fragment
Transmission Control Protocol
Reserved (1-bit); DF (1-bit); MF (1-bit)

46. What is the ARP Operation value for an ARP Reply?
IANA
Length of header in words (32-bit)
2
Electrical/Optical - Mechanical - Functional and Procedural

47. What is ECE?
Application
ECN-Echo
64
88

48. What is the function of ICMP redirect messages?
IANA
Reset
Used by routers to notify hosts of another router on the data link that should be used for a particular destination
4

49. What is ICMP Type 0?
255.255.255.240
Address Resolution Protocol
Echo Reply
Internet

50. Displays the ARP cache of a router
Router#show arp
Internet Assigned Numbers Authority
Duplicate address checks; Advertise new data-link identifiers; Update the ARP caches of hosts
Internet Service Provider