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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. What is ICMP Type 10?
Router Selection
ICANN
Congestion Window Reduced
They are the same byte - but the names and value interpretations are different

2. What is the ARP Protocol address length value for IPv4?
89
192.0.2.0/24
4
Network interface

3. What mechanisms are used by TCP to provide reliable segment delivery?
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
255.255.255.240
RIRs
Acknowledgements - checksums and timers

4. What TCP/IP protocol suite layer corresponds to the transport layer of the OSI model?
Host-to-host
RFC 791
3
Urgent

5. What field identifies where the TCP encapsulated data fits within the data stream from the sender?
Sequence Number
Router(config-if)#no ip proxy-arp
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Redirect

6. Enables debugging output for ARP transactions
4
Router#debug arp
Internet Control Message Protocol
Acknowledgement

7. What is NIR?
National Internet Registry
Router(config-if)#no ip proxy-arp
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
3

8. What routing protocols are classful?
3
255.255.255.128
The next sequence number that the source expects to receive from the destination
RIPv1 and IGRP

9. What is covered by the TCP Checksum field?
20 octets
Both the TCP header and the encapsulated data
1-2 Network interface; 3 Internet; 4 Host-to-host; 5-7 Application
Local Internet Registry

10. What is PSH?
DSCP (6-bit); ECN (2-bit)
Push
NIRs
Uniquely identify every application in the network

11. What is the IPv4 protocol number for UDP?
17
Per-Hop Behaviour (PHB)
Identifier; Flags and Fragmentation Offset
Loose source routing; Strict source routing; Record route; Timestamp

12. What is ICMP?
LIRs
Internet Control Message Protocol
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
Router(config-if)#no ip proxy-arp

13. Which IPv4 address range is reserved for loopback testing?
127.0.0.0/8
Application
Network interface
198.18.0.0/15

14. What is a TCP Acknowledgement Number?
198.18.0.0/15
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
255.255.255.224
The next sequence number that the source expects to receive from the destination

15. Which RFC defines the private IPv4 address ranges?
Padding of zeros to ensure that the header ends on a 32-bit boundary
Transmission Control Protocol
RFC 1918
Used by a host to obtain the IP address associated with another host's MAC address

16. Configures how long a dynamically learned protocol address and its corresponding hardware address remains in the ARP cache
255.255.255.192
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
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254
Router(config-if)#arp timeout {seconds}

17. What is the format of the ToS byte in the IPv4 header?
3
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
IANA
127.0.0.0/8

18. What is the IPv4 Protocol number for IP in IP encapsulation?
4
Echo
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Used by IRDP on some operating systems to discover local routers

19. Who is responsible for maintaining the official assignments of TCP and UDP port numbers for specific uses?
IANA
Router Advertisement
127.0.0.0/8
The next sequence number that the source expects to receive from the destination

20. How can the receiver determine the size of a packet's data payload based on the IPv4 header?
Router#show arp
Identifier; Flags and Fragmentation Offset
Subtract Header Length field from Total Length field
Used by routers to notify hosts of another router on the data link that should be used for a particular destination

21. What is the format of the Flags field in the IPv4 header?
Reserved (1-bit); DF (1-bit); MF (1-bit)
89
255.255.255.128
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)

22. Who allocates IP address space and AS numbers to RIRs?
6
Echo Reply
IANA
Acknowledgements - checksums and timers

23. Which IPv4 address range is reserved for link-local addresses when DHCP fails?
Padding of zeros to ensure that the header ends on a 32-bit boundary
169.254.0.0/16
8
4

24. What is the format of the DiffServ byte?
Subtract Header Length field from Total Length field
Router(config-if)#no ip redirects
89
DSCP (6-bit); ECN (2-bit)

25. What is the other name for the TCP Header Length field?
ECN-Echo
URG flag set
Data Offset
Internet Service Provider

26. What is ICMP Type 5?
47
Redirect
URG flag set
Time Exceeded

27. What is ICMP Type 9?
Number of octets to be added to the Sequence Number to indicate the end of the urgent data
Router Advertisement
Data Offset
Internet Corporation for Assigned Network Numbers

28. Who administers and registers public IP address space and AS numbers within a country or economic unit?
Open Systems Interconnection
Largest segment size that the sender is willing to accept
Router Advertisement
NIRs

29. What is the format of the ToS field?
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
Address Resolution Protocol
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)
1

30. What is the format of an ICMP header?
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control
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);
17

31. Which IPv4 address range is reserved for use in documentation and example code?
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control
0x0800
192.0.2.0/24
Used by a host to obtain the IPv4 address associated with its own MAC address

32. Who are LIRs?
0.0.0.0/8
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
Mostly large ISPs - enterprises - or academic institutions
Used by a host to obtain the IP address associated with another host's MAC address

33. What is the ARP Operation value for an ARP Request?
1
An ARP request issued by a host with its own IPv4 address as the target address
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
Mostly large ISPs - enterprises - or academic institutions

34. What is LIR?
255.255.255.224
Application
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
Local Internet Registry

35. What are the private IPv4 address ranges?
47
Internet Protocol
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
8

36. What is the format of a UDP header?
Internet Service Provider
Address Resolution Protocol
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)
Don't Fragment

37. What is the IPv4 Protocol number for IGMP?
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);
Subtract Header Length field from Total Length field
Time to Live

38. What is SYN?
127.0.0.0/8
ECN-Echo
Synchronize
Each router decrements the TTL

39. Deletes dynamic entries from the ARP cache
Router#clear arp-cache [{interface {interface}} | {ip-address}]
255.255.255.128
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)
1

40. What is IANA?
Internet Assigned Numbers Authority
Local Internet Registry
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)
Identifier; Flags and Fragmentation Offset

41. What is the most commonly used Option field in the TCP header?
Maximum Segment Size (MSS)
Router(config)#ip arp proxy disable
Internet Assigned Numbers Authority
ECN-Echo

42. What are the most common IP version numbers?
RFC 1918
IPv4 and IPv6
Sequence Number
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control

43. What mechanism is used by TCP to regulate the flow of segments?
Windowing
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254
192.88.99.0/24
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

44. What is the the MF-bit in the IPv4 header?
Router Selection
Padding of zeros to ensure that the header ends on a 32-bit boundary
More Fragments follow
Used by a host to obtain the IPv4 address associated with its own MAC address

45. What is the format of a TCP header?
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
Method where routers - by responding to ARP requests for IP addresses in different subnets - make themselves available to hosts with no default gateway configured
4
Regional Internet Registry

46. What is the format of the Flags field in the TCP header?
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
2
Congestion Window Reduced
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control

47. What is ACK?
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
Acknowledgement
Loose source routing; Strict source routing; Record route; Timestamp
DSCP (6-bit); ECN (2-bit)

48. What are the IP Precedence values?
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control
Time to Live
Subtract Header Length field from Total Length field

49. Who owns the processes by which public IP address space and AS numbers are allocated and assigned?
ICANN
Both the TCP header and the encapsulated data
Regional Internet Registry
Synchronize

50. What is CWR?
47
Congestion Window Reduced
Host-to-host
1