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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 LIR?
Local Internet Registry
Router#clear arp-cache [{interface {interface}} | {ip-address}]
Number of octets to be added to the Sequence Number to indicate the end of the urgent data
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

2. What is prefix /26 in decimal notation?
255.255.255.192
89
ICMP Router Discovery Protocol
255.255.255.224

3. What is the IPv4 Protocol number for TCP?
6
Router(config-if)#arp timeout {seconds}
1
Synchronize

4. What is the purpose of a socket?
1
Echo Reply
198.18.0.0/15
Uniquely identify every application in the network

5. What is the format of an ARP packet?
255.255.255.224
RFC 1918
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
Sequence Numbers

6. What is the ARP Operation value for a Reverse ARP Request?
3
RIRs
Router(config-if)#arp timeout {seconds}
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment

7. Who are LIRs?
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Mostly large ISPs - enterprises - or academic institutions
88
Router(config)#arp {ip-address} {mac-address} arpa

8. What TCP/IP protocol suite layer corresponds to the session - presentation and application layers of the OSI model?
Application
ICANN and IANA
Internet Service Provider
National Internet Registry

9. What is the most commonly used Option field in the TCP header?
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
Internet Control Message Protocol
Used by a host to obtain the IPv4 address associated with its own MAC address
Maximum Segment Size (MSS)

10. What is the prerequisite for using the Urgent Pointer field in the TCP header?
9
Router(config-if)#no ip proxy-arp
1
URG flag set

11. What is the IPv4 Protocol number for GRE?
ICANN
47
Host-to-host
4

12. What is the IPv4 Protocol number for ICMP?
1
0.0.0.0/8
ICANN and IANA
Identifier; Flags and Fragmentation Offset

13. Which RFC defines the private IPv4 address ranges?
Length of header in words (32-bit)
1
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
RFC 1918

14. Why must the header checksum of an IPv4 packet be recalculated at every router?
Each router decrements the TTL
4
RFC 1918
ICANN and IANA

15. What is prefix /25 in decimal notation?
255.255.255.192
Internet Protocol
Minimize Delay (1-bit); Maximise Throughput (1-bit); Maximise Reliability (1-bit); Minimize Monetary Cost (1-bit)
255.255.255.128

16. What is ICMP Type 0?
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
Echo Reply
ICANN and IANA
Router Selection

17. What is the format of the DiffServ byte?
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111
Router Selection
DSCP (6-bit); ECN (2-bit)
Router(config-if)#arp timeout {seconds}

18. Which IPv4 address range is reserved for IPv6 to IPv4 (6to4) relays (RFC 3068)?
192.88.99.0/24
RFC 3330
4
Router Selection

19. Who administers and registers IP address space and AS numbers within a region?
Data Offset
Router Advertisement
Router#debug arp
RIRs

20. What is the ARP Operation value for an ARP Reply?
2
Used by IRDP on some operating systems to discover local routers
Internet Service Provider
Internet Assigned Numbers Authority

21. What is the IPv4 Protocol number for IP in IP encapsulation?
Loose source routing; Strict source routing; Record route; Timestamp
Internet
The next sequence number that the source expects to receive from the destination
4

22. What is the IPv4 Protocol number for EIGRP?
Network interface
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)
RIRs
88

23. What is the content of the TCP Window Size field?
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
Duplicate address checks; Advertise new data-link identifiers; Update the ARP caches of hosts
Address Resolution Protocol
4

24. What is the recommended default TTL?
4
Internet Corporation for Assigned Network Numbers
Synchronize
64

25. What is the value of the TCP Reserved field?
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
IANA
0
ICMP Router Discovery Protocol

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

27. Who is responsible for the global coordination of the DNS Root - IP addressing - and other Internet protocol resources?
IANA
Used by a host to obtain the IP address associated with another host's MAC address
Padding of zeros to ensure that the header ends on a 32-bit boundary
4

28. Who administers and registers public IP address space and AS numbers within a country or economic unit?
NIRs
CWR (1-bit); ECE (1-bit); URG (1-bit); ACK (1-bit); PSH (1-bit); RST (1-bit); SYN (1-bit); FIN (1-bit)
20 octets
Used by a host to obtain the IP address associated with another host's MAC address

29. What is RST?
URG flag set
255.255.255.248
Reset
They are the same byte - but the names and value interpretations are different

30. Displays the ARP cache of a router
Per-Hop Behaviour (PHB)
Router#show arp
Windowing
Local Internet Registry

31. What is the function of ICMP router advertisement and router selection messages?
Router(config-if)#arp timeout {seconds}
ICANN
Used by IRDP on some operating systems to discover local routers
Router Selection

32. Which RFC defines the special use IPv4 address ranges?
RFC 3330
1
Router(config-if)#no ip proxy-arp
Acknowledgement

33. What mechanisms are used by TCP to provide reliable segment delivery?
Internet Control Message Protocol
Sequence Number + Data payload octets + 1
Acknowledgements - checksums and timers
Protocols that don't include subnet masks in their routing updates

34. What is IP?
Acknowledgement
2
255.255.255.252
Internet Protocol

35. Which IPv4 address range is reserved for self-identification on a local subnet?
Loose source routing; Strict source routing; Record route; Timestamp
0x0800
0.0.0.0/8
More Fragments follow

36. Who can assign IP address space to end user organizations?
Router Selection
Transmission Control Protocol
All Internet Registries
IANA

37. What is the ARP Operation value for an Inverse ARP Reply?
2
Redirect
9
Both the TCP header and the encapsulated data

38. What is the ARP Protocol type value for IPv4?
Maximum Segment Size (MSS)
Sequence Number
Internet Assigned Numbers Authority
0x0800

39. What is IANA?
Internet Assigned Numbers Authority
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
4
RIPv1 and IGRP

40. What is the maximum length of an IPv4 header?
Padding of zeros to ensure that the header ends on a 32-bit boundary
More Fragments follow
60 octets
255.255.255.192

41. What is the first octet rule for IPv4 address classes in decimal?
4
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254
1
NIRs

42. What are the private IPv4 address ranges?
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
Time to Live
Regional Internet Registry
127.0.0.0/8

43. What is the format of a UDP header?
Sequence Numbers
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)
ICMP Router Discovery Protocol
Router#show arp

44. What is CWR?
Congestion Window Reduced
Synchronize
Router(config-if)#no ip proxy-arp
Router#debug arp

45. What routing protocols are classful?
Destination Unreachable
Push
8
RIPv1 and IGRP

46. Specifies the format in which subnet masks are displayed in show command output
4
Both the TCP header and the encapsulated data
Host-to-host
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}

47. How does the layers of the TCP/IP protocol suite map to the 7 layers of the OSI model?
255.255.255.240
IANA
An ARP request issued by a host with its own IPv4 address as the target address
1-2 Network interface; 3 Internet; 4 Host-to-host; 5-7 Application

48. Which protocol has mostly replaced Reverse ARP?
DSCP (6-bit); ECN (2-bit)
192.0.2.0/24
192.88.99.0/24
DHCP

49. Which IPv4 address range is reserved for loopback testing?
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
Acknowledgements - checksums and timers
127.0.0.0/8
NIRs

50. What is the minimum length of an IPv4 header?
10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
20 octets
Subtract Header Length field from Total Length field