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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. Who are LIRs?
17
Router(config-if)#no ip redirects
Mostly large ISPs - enterprises - or academic institutions
DHCP

2. What TCP/IP protocol suite layer corresponds to the network layer of the OSI model?
Internet
An ARP request issued by a host with its own IPv4 address as the target address
LIRs
Application

3. What is the value of the TCP Reserved field?
Used by a host to obtain the IPv4 address associated with its own MAC address
NIRs
National Internet Registry
0

4. What is the other name for the TCP Header Length field?
Router#show arp
Router#debug arp
Congestion Window Reduced
Data Offset

5. What is the IPv4 Protocol number for EIGRP?
Method where routers - by responding to ARP requests for IP addresses in different subnets - make themselves available to hosts with no default gateway configured
255.255.255.224
88
RFC 791

6. What is the format of the ToS field?
Sequence Number
ECN-Echo
Destination Unreachable
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)

7. What is the IPv4 Protocol number for IP in IP encapsulation?
Push
DSCP (6-bit); ECN (2-bit)
4
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment

8. What is the format of a UDP header?
IANA
RIRs
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)
192.0.2.0/24

9. Disables proxy ARP on all interfaces
Length of header in words (32-bit)
Internet Assigned Numbers Authority
Transmission Control Protocol
Router(config)#ip arp proxy disable

10. What is ARP?
Regional Internet Registry
Network interface
Address Resolution Protocol
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields

11. What is CWR?
RFC 3330
Internet Service Provider
Congestion Window Reduced
Padding of zeros to ensure that the header ends on a 32-bit boundary

12. What is added after the option field in the IPv4 header?
0.0.0.0/8
Open Systems Interconnection
Padding of zeros to ensure that the header ends on a 32-bit boundary
Uniquely identify every application in the network

13. What is gratuitous ARP?
1
An ARP request issued by a host with its own IPv4 address as the target address
Subtract Header Length field from Total Length field
Largest segment size that the sender is willing to accept

14. Disables proxy ARP on an interface
192.0.2.0/24
1-2 Network interface; 3 Internet; 4 Host-to-host; 5-7 Application
Router(config-if)#no ip proxy-arp
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields

15. 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
Synchronize
Used by a host to obtain the IP address associated with another host's MAC address
Maximum Segment Size (MSS)

16. What is the format of the DiffServ byte?
DSCP (6-bit); ECN (2-bit)
Application
2
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

17. What is the most commonly used Option field in the TCP header?
Reset
Maximum Segment Size (MSS)
Destination Unreachable
Reserved (1-bit); DF (1-bit); MF (1-bit)

18. What is the prerequisite for using the Urgent Pointer field in the TCP header?
They are the same byte - but the names and value interpretations are different
Sequence Numbers
URG flag set
Number of octets to be added to the Sequence Number to indicate the end of the urgent data

19. Which RFC defines the private IPv4 address ranges?
2
RFC 1918
Padding of zeros to ensure that the header ends on a 32-bit boundary
2

20. What is ECE?
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
Subtract Header Length field from Total Length field
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
ECN-Echo

21. What TCP/IP protocol suite layer corresponds to the physical and data link layers of the OSI model?
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111
6
Internet Control Message Protocol
Network interface

22. Which RFC defines the special use IPv4 address ranges?
Each router decrements the TTL
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control
255.255.255.248
RFC 3330

23. What is the the MF-bit in the IPv4 header?
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);
Identifier; Flags and Fragmentation Offset
More Fragments follow
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

24. Who is responsible for maintaining the official assignments of TCP and UDP port numbers for specific uses?
17
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control
IANA
Host-to-host

25. What is ISP?
Internet Assigned Numbers Authority
0.0.0.0/8
Internet Service Provider
An ARP request issued by a host with its own IPv4 address as the target address

26. What are the steps to subnet an IPv4 address?
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
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
Echo
1

27. What is the IPv4 protocol number for UDP?
1
Router#show arp
4
17

28. What is ICMP Type 11?
Time Exceeded
47
The next sequence number that the source expects to receive from the destination
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)

29. What are the uses of gratuitous ARP?
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254
Sequence Number
Router#clear arp-cache [{interface {interface}} | {ip-address}]
Duplicate address checks; Advertise new data-link identifiers; Update the ARP caches of hosts

30. What is the ARP Protocol type value for IPv4?
Both the TCP header and the encapsulated data
0x0800
Router(config)#ip arp proxy disable
Router#clear arp-cache [{interface {interface}} | {ip-address}]

31. Which IPv4 address range is reserved for link-local addresses when DHCP fails?
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
Each router decrements the TTL
169.254.0.0/16
255.255.255.192

32. What is IRDP?
1
192.0.2.0/24
ICMP Router Discovery Protocol
192.88.99.0/24

33. What is the format of the TCP Header Length field?
Length of header in words (32-bit)
Congestion Window Reduced
Per-Hop Behaviour (PHB)
Sequence Number + Data payload octets + 1

34. What is the ARP Hardware type value for Ethernet?
1
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)
8
Urgent

35. Who assigns IP address space to its own customers?
ECN-Echo
LIRs
60 octets
Internet Assigned Numbers Authority

36. Enables debugging output for ARP transactions
Length of header in words (32-bit)
Router#debug arp
More Fragments follow
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111

37. What is the Fragment Offset field in the IPv4 header?
Acknowledgements - checksums and timers
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
Data Offset
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)

38. What is prefix /26 in decimal notation?
An ARP request issued by a host with its own IPv4 address as the target address
Sequence Number
Router Selection
255.255.255.192

39. What is the difference between the ToS and the DiffServ byte?
LIRs
They are the same byte - but the names and value interpretations are different
Used by routers to notify hosts of another router on the data link that should be used for a particular destination
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)

40. Disables the sending of ICMP redirect messages
60 octets
Router(config-if)#no ip redirects
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);
Push

41. What is IP?
RIRs
Internet Protocol
Router(config)#arp {ip-address} {mac-address} arpa
RIRs

42. What TCP/IP protocol suite layer corresponds to the session - presentation and application layers of the OSI model?
Application
Padding of zeros to ensure that the header ends on a 32-bit boundary
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);
The next sequence number that the source expects to receive from the destination

43. What mechanism is used by TCP to regulate the flow of segments?
0.0.0.0/8
Protocols that don't include subnet masks in their routing updates
Socket
Windowing

44. What is the ARP Protocol address length value for IPv4?
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)
4
8
Redirect

45. What is the ARP Operation value for an Inverse ARP Request?
60 octets
255.255.255.128
88
8

46. What is the ARP Operation value for a Reverse ARP Reply?
Internet Service Provider
Router(config)#arp {ip-address} {mac-address} arpa
Don't Fragment
4

47. What is a TCP Acknowledgement Number?
DSCP (6-bit); ECN (2-bit)
The next sequence number that the source expects to receive from the destination
Acknowledgement
255.255.255.240

48. Which IPv4 address range is reserved for benchmark testing of Internet devices (RFC 2544)?
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
RIPv1 and IGRP
198.18.0.0/15
Windowing

49. What is the format of an ARP packet?
Length of header in words (32-bit)
6
Router Advertisement
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

50. What is prefix /27 in decimal notation?
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
IPv4 and IPv6
255.255.255.224
Internet Service Provider