Test your basic knowledge |

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 the ARP Hardware address length value for Ethernet?
Router#show arp
6
Address Resolution Protocol
0.0.0.0/8

2. What is the first octet rule for IPv4 address classes in binary?
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
ECN-Echo
4

3. What is prefix /28 in decimal notation?
255.255.255.240
64
1
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment

4. What is prefix /30 in decimal notation?
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
88
192.0.2.0/24
255.255.255.252

5. Deletes dynamic entries from the ARP cache
Router(config-if)#no ip proxy-arp
Router#clear arp-cache [{interface {interface}} | {ip-address}]
ECN-Echo
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

6. What are the private IPv4 address ranges?
Mostly large ISPs - enterprises - or academic institutions
NIRs
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Destination Unreachable

7. What is IANA?
Internet Assigned Numbers Authority
Mostly large ISPs - enterprises - or academic institutions
Network interface
Sequence Number

8. What are the most common IP version numbers?
RIPv1 and IGRP
Subtract Header Length field from Total Length field
6
IPv4 and IPv6

9. What is the IPv4 protocol number for UDP?
46
1
Loose source routing; Strict source routing; Record route; Timestamp
17

10. What is proxy ARP?
Method where routers - by responding to ARP requests for IP addresses in different subnets - make themselves available to hosts with no default gateway configured
DHCP
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
6

11. What are the uses of gratuitous ARP?
Router Selection
Duplicate address checks; Advertise new data-link identifiers; Update the ARP caches of hosts
Destination Unreachable
The next sequence number that the source expects to receive from the destination

12. Why must the header checksum of an IPv4 packet be recalculated at every router?
Largest segment size that the sender is willing to accept
Echo
255.255.255.128
Each router decrements the TTL

13. What is the minimum length of an IPv4 header?
Router(config-if)#no ip proxy-arp
Used by IRDP on some operating systems to discover local routers
1-2 Network interface; 3 Internet; 4 Host-to-host; 5-7 Application
20 octets

14. What is ICMP Type 11?
Time Exceeded
Urgent
47
Host-to-host

15. What is the ARP Hardware type value for Ethernet?
Destination Unreachable
1
46
2

16. What is the Fragment Offset field in the IPv4 header?
47
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
Used by routers to notify hosts of another router on the data link that should be used for a particular destination

17. What is the format of the ToS byte in the IPv4 header?
2
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
Protocols that include subnet masks in their routing updates
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

18. Who administers and registers IP address space and AS numbers within a region?
Router#clear arp-cache [{interface {interface}} | {ip-address}]
RIRs
Time to Live
RIPv1 and IGRP

19. What is ICMP Type 0?
Echo Reply
Application
Loose source routing; Strict source routing; Record route; Timestamp
1-2 Network interface; 3 Internet; 4 Host-to-host; 5-7 Application

20. What mechanism is used by TCP to regulate the flow of segments?
Padding of zeros to ensure that the header ends on a 32-bit boundary
Address Resolution Protocol
Windowing
Internet Service Provider

21. What is covered by the TCP Checksum field?
ECN-Echo
Both the TCP header and the encapsulated data
8
Router(config-if)#no ip redirects

22. Who are LIRs?
Mostly large ISPs - enterprises - or academic institutions
2
17
Router#clear arp-cache [{interface {interface}} | {ip-address}]

23. What IPv4 header fields are used for fragmentation?
Identifier; Flags and Fragmentation Offset
88
89
IANA

24. What is the format of the Flags field in the IPv4 header?
0.0.0.0/8
Reserved (1-bit); DF (1-bit); MF (1-bit)
Data Offset
Largest segment size that the sender is willing to accept

25. What TCP/IP protocol suite layer corresponds to the transport layer of the OSI model?
Host-to-host
Windowing
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
Maximum Segment Size (MSS)

26. What are the steps to subnet an IPv4 address?
Internet Corporation for Assigned Network Numbers
0
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
Windowing

27. What mechanism is used by TCP to provided ordered segment delivery?
Sequence Numbers
Push
Sequence Number
Router(config)#arp {ip-address} {mac-address} arpa

28. Disables the sending of ICMP redirect messages
All Internet Registries
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);
Application

29. What is ICMP Type 8?
Echo
3
Internet Service Provider
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111

30. Who allocates IP address space and AS numbers to RIRs?
4
Echo
4
IANA

31. Disables proxy ARP on an interface
Don't Fragment
Method where routers - by responding to ARP requests for IP addresses in different subnets - make themselves available to hosts with no default gateway configured
LIRs
Router(config-if)#no ip proxy-arp

32. What is the IPv4 Protocol number for TCP?
6
198.18.0.0/15
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control
Host-to-host

33. What is ARP?
Electrical/Optical - Mechanical - Functional and Procedural
The next sequence number that the source expects to receive from the destination
Address Resolution Protocol
RFC 791

34. What is the the MF-bit in the IPv4 header?
Acknowledgement
RIPv1 and IGRP
LIRs
More Fragments follow

35. What is the IPv4 Protocol number for OSPF?
6
DHCP
Network interface
89

36. What is the format of the TCP Header Length field?
Length of header in words (32-bit)
Don't Fragment
6
Address Resolution Protocol

37. What is the function of ICMP redirect messages?
Used by routers to notify hosts of another router on the data link that should be used for a particular destination
198.18.0.0/15
Address Resolution Protocol
Sequence Number + Data payload octets + 1

38. What is CWR?
Congestion Window Reduced
Used by a host to obtain the IP address associated with another host's MAC address
Largest segment size that the sender is willing to accept
Length of header in words (32-bit)

39. Which RFC defines the private IPv4 address ranges?
Synchronize
Router#clear arp-cache [{interface {interface}} | {ip-address}]
RFC 1918
IPv4 and IPv6

40. What is gratuitous ARP?
An ARP request issued by a host with its own IPv4 address as the target address
Regional Internet Registry
Data Offset
Internet Corporation for Assigned Network Numbers

41. Enables debugging output for ARP transactions
Per-Hop Behaviour (PHB)
Router#debug arp
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
4

42. What is ACK?
Acknowledgement
88
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)
The next sequence number that the source expects to receive from the destination

43. What is the ARP Operation value for a Reverse ARP Request?
3
DHCP
46
Local Internet Registry

44. What is ICMP?
More Fragments follow
Urgent
ICMP Router Discovery Protocol
Internet Control Message Protocol

45. What is the IPv4 Protocol number for IP in IP encapsulation?
Router(config)#arp {ip-address} {mac-address} arpa
6
4
Redirect

46. What is the ARP Operation value for an ARP Reply?
2
DHCP
Destination Unreachable
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);

47. What is the formula to calculate the next Sequence Number based on the Sequence Number of the current TCP segment?
Sequence Number + Data payload octets + 1
Router Advertisement
Internet Control Message Protocol
All Internet Registries

48. What mechanisms are used by TCP to provide reliable segment delivery?
Application
47
Acknowledgements - checksums and timers
Router#clear arp-cache [{interface {interface}} | {ip-address}]

49. What is ECE?
ECN-Echo
Sequence Number
2
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}

50. Which IPv4 address range is reserved for IPv6 to IPv4 (6to4) relays (RFC 3068)?
20 octets
Sequence Number
Sequence Numbers
192.88.99.0/24