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IPV4 Addressing

Subject : it-skills

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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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. Which IPv4 address range is reserved for benchmark testing of Internet devices (RFC 2544)?
198.18.0.0/15
Reset
Echo
Used by routers to notify hosts of another router on the data link that should be used for a particular destination

2. What is the ARP Operation value for an ARP Request?
Protocols that include subnet masks in their routing updates
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
1

3. What is the first octet rule for IPv4 address classes in decimal?
46
Method where routers - by responding to ARP requests for IP addresses in different subnets - make themselves available to hosts with no default gateway configured
Length of header in words (32-bit)
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254

4. What TCP/IP protocol suite layer corresponds to the transport layer of the OSI model?
Acknowledgement
Per-Hop Behaviour (PHB)
Data Offset
Host-to-host

5. What is gratuitous ARP?
Subtract Header Length field from Total Length field
An ARP request issued by a host with its own IPv4 address as the target address
1
88

6. What are the most common IP version numbers?
IPv4 and IPv6
IANA
2
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);

7. What routing protocols are classful?
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
They are the same byte - but the names and value interpretations are different
0x0800
RIPv1 and IGRP

8. What is ICMP Type 8?
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)
RFC 1918
Router#clear arp-cache [{interface {interface}} | {ip-address}]
Echo

9. What is IRDP?
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)
9
Congestion Window Reduced
ICMP Router Discovery Protocol

10. What is CWR?
IANA
Congestion Window Reduced
Used by routers to notify hosts of another router on the data link that should be used for a particular destination
Internet Assigned Numbers Authority

11. What are the private IPv4 address ranges?
Used by IRDP on some operating systems to discover local routers
ICANN and IANA
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Synchronize

12. Who is responsible for the global coordination of the DNS Root - IP addressing - and other Internet protocol resources?
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);
IANA
Sequence Numbers
Acknowledgement

13. Who owns the processes by which public IP address space and AS numbers are allocated and assigned?
ICANN
Final
Echo
Host-to-host

14. What is prefix /26 in decimal notation?
Local Internet Registry
1
Router(config)#ip arp proxy disable
255.255.255.192

15. What is the format of a TCP header?
Internet Service Provider
Used by IRDP on some operating systems to discover local routers
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
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)

16. What is the IPv4 Protocol number for GRE?
The next sequence number that the source expects to receive from the destination
17
47
URG flag set

17. What is SYN?
Padding of zeros to ensure that the header ends on a 32-bit boundary
Synchronize
Router Advertisement
Sequence Numbers

18. What is prefix /29 in decimal notation?
88
Per-Hop Behaviour (PHB)
255.255.255.248
Router(config)#ip arp proxy disable

19. What is the Fragment Offset field in the IPv4 header?
Router#clear arp-cache [{interface {interface}} | {ip-address}]
Internet Assigned Numbers Authority
Protocols that don't include subnet masks in their routing updates
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment

20. What is the difference between the ToS and the DiffServ byte?
Internet Service Provider
They are the same byte - but the names and value interpretations are different
Data Offset
Internet Assigned Numbers Authority

21. What is the value of the TCP Reserved field?
Acknowledgement
Host-to-host
0
9

22. What is TCP?
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
Transmission Control Protocol
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
Router(config)#ip arp proxy disable

23. What mechanisms are used by TCP to provide reliable segment delivery?
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
2
Mostly large ISPs - enterprises - or academic institutions
Acknowledgements - checksums and timers

24. What is the ARP Operation value for an Inverse ARP Reply?
RIRs
9
Identifier; Flags and Fragmentation Offset
169.254.0.0/16

25. What is the format of the TCP Header Length field?
6
Push
Reserved (1-bit); DF (1-bit); MF (1-bit)
Length of header in words (32-bit)

26. What is the ARP Operation value for an Inverse ARP Request?
Reserved (1-bit); DF (1-bit); MF (1-bit)
1
8
4

27. What is the minimum length of an IPv4 header?
Data Offset
198.18.0.0/15
20 octets
IANA

28. What IPv4 header fields are used for fragmentation?
Identifier; Flags and Fragmentation Offset
Internet Protocol
4
IANA

29. What is ICMP Type 10?
Router Selection
Router#show arp
255.255.255.240
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}

30. Who are LIRs?
Mostly large ISPs - enterprises - or academic institutions
88
Length of header in words (32-bit)
17

31. What is PSH?
Push
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Padding of zeros to ensure that the header ends on a 32-bit boundary
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

32. What is ICMP Type 11?
Router#debug arp
192.88.99.0/24
Time Exceeded
Sequence Number

33. Specifies the format in which subnet masks are displayed in show command output
The next sequence number that the source expects to receive from the destination
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
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
255.255.255.224

34. What is the first octet rule for IPv4 address classes in binary?
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
255.255.255.128
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111
6

35. Deletes dynamic entries from the ARP cache
Windowing
Router#clear arp-cache [{interface {interface}} | {ip-address}]
Don't Fragment
Used by a host to obtain the IPv4 address associated with its own MAC address

36. What is URG?
Router(config-if)#no ip redirects
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
Urgent
64

37. Who can assign IP address space to end user organizations?
Open Systems Interconnection
All Internet Registries
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);
RFC 3330

38. What is the ARP Protocol type value for IPv4?
8
Address Resolution Protocol
0x0800
Sequence Number

39. What is a TCP Acknowledgement Number?
Used by a host to obtain the IPv4 address associated with its own MAC address
The next sequence number that the source expects to receive from the destination
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
169.254.0.0/16

40. What is ICMP Type 9?
Router Advertisement
255.255.255.248
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
RFC 791

41. What is LIR?
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
Redirect
Local Internet Registry
ICMP Router Discovery Protocol

42. What is proxy ARP?
255.255.255.240
Duplicate address checks; Advertise new data-link identifiers; Update the ARP caches of hosts
Local Internet Registry
Method where routers - by responding to ARP requests for IP addresses in different subnets - make themselves available to hosts with no default gateway configured

43. What is the content of the the Urgent Pointer field in the TCP header?
Sequence Numbers
Network interface
Router Advertisement
Number of octets to be added to the Sequence Number to indicate the end of the urgent data

44. What is added after the Option field in the TCP header?
Padding of zeros to ensure that the header ends on a 32-bit boundary
Reset
Regional Internet Registry
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control

45. What is the IPv4 Protocol number for IP in IP encapsulation?
Used by a host to obtain the IP address associated with another host's MAC address
4
Time Exceeded
URG flag set

46. What is the format of the Flags field in the TCP header?
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Mostly large ISPs - enterprises - or academic institutions
Push
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)

47. Who allocates IP address space and AS numbers to RIRs?
Don't Fragment
IANA
Each router decrements the TTL
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111

48. What mechanism is used by TCP to regulate the flow of segments?
Router Selection
Transmission Control Protocol
Windowing
Push

49. Which IPv4 address range is reserved for self-identification on a local subnet?
1
Maximum Segment Size (MSS)
Application
0.0.0.0/8

50. Who is responsible for maintaining the official assignments of TCP and UDP port numbers for specific uses?
IANA
20 octets
Internet Service Provider
Time Exceeded