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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.
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 maximum length of an IPv4 header?
17
Number of octets to be added to the Sequence Number to indicate the end of the urgent data
60 octets
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111

2. Which protocol has mostly replaced Reverse ARP?
IANA
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
DHCP
Sequence Number + Data payload octets + 1

3. Which IPv4 address range is reserved for benchmark testing of Internet devices (RFC 2544)?
47
88
198.18.0.0/15
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

4. What is ICMP Type 0?
Sequence Number + Data payload octets + 1
Echo Reply
Host-to-host
Subtract Header Length field from Total Length field

5. What is the format of the ToS byte in the IPv4 header?
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
60 octets
The next sequence number that the source expects to receive from the destination
0.0.0.0/8

6. What is RST?
2
Internet Corporation for Assigned Network Numbers
Reset
Final

7. What is the content of the Maximum Segment Size (MSS) in the Option field of the TCP header?
Largest segment size that the sender is willing to accept
Echo Reply
Echo
46

8. What is the ARP Operation value for an ARP Request?
Sequence Number + Data payload octets + 1
1
Host-to-host
IANA

9. What TCP/IP protocol suite layer corresponds to the physical and data link layers of the OSI model?
Echo Reply
LIRs
More Fragments follow
Network interface

10. What is ECE?
ECN-Echo
2
Internet Service Provider
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

11. What is the Fragment Offset field in the IPv4 header?
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
192.88.99.0/24
Router#show arp
6

12. What is the other name for the TCP Header Length field?
Used by IRDP on some operating systems to discover local routers
1
2
Data Offset

13. What field identifies where the TCP encapsulated data fits within the data stream from the sender?
Both the TCP header and the encapsulated data
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
Sequence Number
Push

14. What is LIR?
Regional Internet Registry
Local Internet Registry
They are the same byte - but the names and value interpretations are different
Router#clear arp-cache [{interface {interface}} | {ip-address}]

15. What is the format of a UDP header?
Address Resolution Protocol
Router#show arp
Router(config-if)#no ip redirects
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)

16. What is FIN?
0x0800
Final
20 octets
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

17. What is the name of the queuing and forwarding of IP packets based on DiffServ?
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
Per-Hop Behaviour (PHB)
DSCP (6-bit); ECN (2-bit)
Sequence Numbers

18. What are the IP Precedence values?
1
Router(config-if)#no ip redirects
2
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control

19. What is the function of ICMP redirect messages?
Subtract Header Length field from Total Length field
17
Internet Assigned Numbers Authority
Used by routers to notify hosts of another router on the data link that should be used for a particular destination

20. What is the ARP Operation value for an Inverse ARP Reply?
Number of octets to be added to the Sequence Number to indicate the end of the urgent data
88
Electrical/Optical - Mechanical - Functional and Procedural
9

21. What is gratuitous ARP?
Reserved (1-bit); DF (1-bit); MF (1-bit)
An ARP request issued by a host with its own IPv4 address as the target address
Push
IPv4 and IPv6

22. Disables proxy ARP on an interface
0.0.0.0/8
Internet Corporation for Assigned Network Numbers
Duplicate address checks; Advertise new data-link identifiers; Update the ARP caches of hosts
Router(config-if)#no ip proxy-arp

23. Enables debugging output for ARP transactions
Router#debug arp
IPv4 and IPv6
Address Resolution Protocol
88

24. What is prefix /27 in decimal notation?
1
0x0800
255.255.255.224
Acknowledgements - checksums and timers

25. What is the DF-bit in the IPv4 header?

26. How does the layers of the TCP/IP protocol suite map to the 7 layers of the OSI model?
Protocols that include subnet masks in their routing updates
89
1-2 Network interface; 3 Internet; 4 Host-to-host; 5-7 Application
255.255.255.248

27. Which IPv4 address range is reserved for self-identification on a local subnet?
Length of header in words (32-bit)
The next sequence number that the source expects to receive from the destination
0.0.0.0/8
RFC 1918

28. Deletes dynamic entries from the ARP cache
Router#clear arp-cache [{interface {interface}} | {ip-address}]
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
Mostly large ISPs - enterprises - or academic institutions
They are the same byte - but the names and value interpretations are different

29. What is the ARP Protocol type value for IPv4?
Router(config-if)#no ip proxy-arp
Redirect
0x0800
ICANN and IANA

30. What is the content of the the Urgent Pointer field in the TCP header?
Router(config)#ip arp proxy disable
Destination Unreachable
Sequence Number + Data payload octets + 1
Number of octets to be added to the Sequence Number to indicate the end of the urgent data

31. What is the ARP Operation value for a Reverse ARP Request?
Protocols that don't include subnet masks in their routing updates
An ARP request issued by a host with its own IPv4 address as the target address
3
46

32. What is the purpose of a socket?
Uniquely identify every application in the network
More Fragments follow
IANA
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

33. What is the ARP Hardware address length value for Ethernet?
Per-Hop Behaviour (PHB)
ECN-Echo
Maximum Segment Size (MSS)
6

34. Which RFC defines the private IPv4 address ranges?
Time to Live
Padding of zeros to ensure that the header ends on a 32-bit boundary
RFC 1918
ICMP Router Discovery Protocol

35. What is the ARP Hardware type value for Ethernet?
Subtract Header Length field from Total Length field
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111
Both the TCP header and the encapsulated data
1

36. What is ICMP Type 10?
Router Selection
Redirect
2
Router Advertisement

37. What is ICMP Type 11?
Time Exceeded
1-2 Network interface; 3 Internet; 4 Host-to-host; 5-7 Application
Redirect
More Fragments follow

38. What are the most frequently used options in the IPv4 header?
ICMP Router Discovery Protocol
2
8
Loose source routing; Strict source routing; Record route; Timestamp

39. Displays the ARP cache of a router
1
Internet Service Provider
Router#show arp
Application

40. What mechanism is used by TCP to provided ordered segment delivery?
Transmission Control Protocol
Sequence Numbers
Router(config-if)#no ip redirects
IANA

41. What is ARP?
Length of header in words (32-bit)
88
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);
Address Resolution Protocol

42. What is TCP?
NIRs
8
169.254.0.0/16
Transmission Control Protocol

43. What is the format of the DiffServ byte?
Router(config-if)#no ip proxy-arp
Router#clear arp-cache [{interface {interface}} | {ip-address}]
DSCP (6-bit); ECN (2-bit)
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields

44. Who administers and registers public IP address space and AS numbers within a country or economic unit?
NIRs
Router(config)#arp {ip-address} {mac-address} arpa
Used by routers to notify hosts of another router on the data link that should be used for a particular destination
Redirect

45. Who group public IPv4 address space by major geographic region?
ICANN and IANA
Congestion Window Reduced
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254
Internet Service Provider

46. Who administers and registers IP address space and AS numbers within a region?
Internet Assigned Numbers Authority
More Fragments follow
RIRs
Router(config-if)#arp timeout {seconds}

47. What is prefix /29 in decimal notation?
255.255.255.248
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
1
Internet Corporation for Assigned Network Numbers

48. What are the private IPv4 address ranges?
Router#clear arp-cache [{interface {interface}} | {ip-address}]
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Length of header in words (32-bit)
All Internet Registries

49. What is ICANN?
20 octets
Sequence Number + Data payload octets + 1
255.255.255.192
Internet Corporation for Assigned Network Numbers

50. Who are LIRs?
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
Mostly large ISPs - enterprises - or academic institutions
Transmission Control Protocol
More Fragments follow