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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 a TCP port number of an application called when it is coupled with the IP address of the server?
Socket
0
More Fragments follow
RFC 3330

2. What are classful routing protocols?

3. Which IPv4 address range is reserved for link-local addresses when DHCP fails?
Acknowledgement
169.254.0.0/16
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

4. 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
2
Reserved (1-bit); DF (1-bit); MF (1-bit)
IANA

5. What is PSH?
Push
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
Sequence Number + Data payload octets + 1
Sequence Number

6. What is the ARP Operation value for an ARP Reply?
The next sequence number that the source expects to receive from the destination
2
0x0800
Internet Service Provider

7. What is IRDP?
ICMP Router Discovery Protocol
Loose source routing; Strict source routing; Record route; Timestamp
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

8. Which IPv4 address range is reserved for loopback testing?
Data Offset
Sequence Number
127.0.0.0/8
Source Port (16-bit); Destination Port (16-bit); UDP Length (16-bit); Checksum (16-bit)

9. What is the ARP Hardware type value for Ethernet?
0 Routine; 1 Priority; 2 Immediate; 3 Flash; 4 Flash Override; 5 Critical; 6 Internetwork Control; 7 Network Control
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
4
1

10. What is the first octet rule for IPv4 address classes in binary?
Sequence Number + Data payload octets + 1
Class A 0; Class B 10; Class C 110; Class D 1110; Class E 1111
Host-to-host
0.0.0.0/8

11. What is the name of the queuing and forwarding of IP packets based on DiffServ?
IANA
Per-Hop Behaviour (PHB)
Data Offset
Used by IRDP on some operating systems to discover local routers

12. What is ARP?
RFC 791
198.18.0.0/15
Router(config-if)#arp timeout {seconds}
Address Resolution Protocol

13. What is the IPv4 Protocol number of RSVP?
46
LIRs
88
Final

14. What is the purpose of a socket?
Uniquely identify every application in the network
Push
DHCP
9

15. Disables proxy ARP on all interfaces
Router(config)#ip arp proxy disable
Loose source routing; Strict source routing; Record route; Timestamp
Internet Control Message Protocol
ECN-Echo

16. What TCP/IP protocol suite layer corresponds to the physical and data link layers of the OSI model?
Network interface
They are the same byte - but the names and value interpretations are different
Offset - in units of eight octets - from the beginning of the original header to the beginning of the fragment
RIRs

17. 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
They are the same byte - but the names and value interpretations are different
Router(config-if)#arp timeout {seconds}
Application

18. What is the content of the Maximum Segment Size (MSS) in the Option field of the TCP header?
Time Exceeded
RFC 3330
2
Largest segment size that the sender is willing to accept

19. What mechanisms are used by TCP to provide reliable segment delivery?
6
1
Router(config-if)#no ip redirects
Acknowledgements - checksums and timers

20. What is the maximum length of an IPv4 header?
255.255.255.192
An ARP request issued by a host with its own IPv4 address as the target address
3
60 octets

21. What is ICMP?
Local Internet Registry
Router(config)#ip arp proxy disable
1
Internet Control Message Protocol

22. What is OSI?
Open Systems Interconnection
Echo
DSCP (6-bit); ECN (2-bit)
255.255.255.252

23. Which IPv4 address range is reserved for use in documentation and example code?
Internet Assigned Numbers Authority
Open Systems Interconnection
Router(config)#arp {ip-address} {mac-address} arpa
192.0.2.0/24

24. What is URG?
Router(config-if)#no ip redirects
Urgent
198.18.0.0/15
The next sequence number that the source expects to receive from the destination

25. What is the difference between the ToS and the DiffServ byte?
Final
IP Precedence (3-bit); ToS (4-bit); Reserved (1-bit)
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields
They are the same byte - but the names and value interpretations are different

26. What is the function of ICMP redirect messages?
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
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
Router#clear arp-cache [{interface {interface}} | {ip-address}]

27. What is RST?
Transmission Control Protocol
Uniquely identify every application in the network
An ARP request issued by a host with its own IPv4 address as the target address
Reset

28. What is covered by the TCP Checksum field?
Both the TCP header and the encapsulated data
Regional Internet Registry
IANA
Router(config-if)#no ip redirects

29. What is IANA?
ECN-Echo
Internet Assigned Numbers Authority
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254
An ARP request issued by a host with its own IPv4 address as the target address

30. What is the format of an ICMP header?
IANA
All Internet Registries
Open Systems Interconnection
Type (8-bit); Code (8-bit); Checksum (16-bit); Variable fields

31. What is the format of an ARP packet?
255.255.255.252
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
2
RIRs

32. What is prefix /27 in decimal notation?
255.255.255.224
192.0.2.0/24
Reset
Echo Reply

33. What is FIN?
RFC 3330
The next sequence number that the source expects to receive from the destination
Host-to-host
Final

34. Specifies the format in which subnet masks are displayed in show command output
127.0.0.0/8
Router#clear arp-cache [{interface {interface}} | {ip-address}]
Router(config)#ip netmask-format {bit-count | decimal | hexadecimal}
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

35. What is the formula to calculate the next Sequence Number based on the Sequence Number of the current TCP segment?
Each router decrements the TTL
1
Sequence Number + Data payload octets + 1
Application

36. What is ICMP Type 8?
Internet
Echo
6
Internet Protocol

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

38. What are classless routing protocols?
Padding of zeros to ensure that the header ends on a 32-bit boundary
Router#clear arp-cache [{interface {interface}} | {ip-address}]
255.255.255.252
Protocols that include subnet masks in their routing updates

39. What is prefix /28 in decimal notation?
255.255.255.240
Internet Service Provider
Class A 1-126; Class B 128-191; Class C 192-223; Class D 224-239; Class E 240-254
Regional Internet Registry

40. Disables proxy ARP on an interface
Router(config-if)#no ip proxy-arp
RFC 1918
Used by a host to obtain the IPv4 address associated with its own MAC address
Redirect

41. What is the ARP Operation value for an Inverse ARP Reply?
IANA
9
89
Application

42. What is the ARP Operation value for a Reverse ARP Request?
3
IANA
RFC 1918
0.0.0.0/8

43. What is ACK?
IANA
Padding of zeros to ensure that the header ends on a 32-bit boundary
LIRs
Acknowledgement

44. What is the ARP Operation value for an Inverse ARP Request?
Acknowledgement
Router(config)#arp {ip-address} {mac-address} arpa
DSCP (6-bit); ECN (2-bit)
8

45. What is the format of the TCP Header Length field?
Sequence Number + Data payload octets + 1
Length of header in words (32-bit)
Don't Fragment
Time to Live

46. What is the format of the DiffServ byte?
DSCP (6-bit); ECN (2-bit)
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
255.255.255.128
Internet Control Message Protocol

47. What is the ARP Protocol address length value for IPv4?
RIPv1 and IGRP
192.88.99.0/24
4
They are the same byte - but the names and value interpretations are different

48. How can the receiver determine the size of a packet's data payload based on the IPv4 header?
192.88.99.0/24
255.255.255.252
Subtract Header Length field from Total Length field
Echo

49. What is prefix /26 in decimal notation?
Destination Unreachable
Sequence Number
Internet Protocol
255.255.255.192

50. What is the function of ICMP router advertisement and router selection messages?
Internet Corporation for Assigned Network Numbers
Used by IRDP on some operating systems to discover local routers
Reset
255.255.255.252