CCNA interview questions part-2
51. Which addresses are INCORRECTLY paired with their class?
* 128 to 191, Class B
* 192 to 223 Class B
* 128 to 191, Class C
* 192 to 223, Class C
Correct answer: B & C
Address classes are: 1 to 126, Class A; 128 to 191, Class B, 192 to 223, Class C; 224 to 239, Class D; and
52. to 255, Class E. The first octet rule states that the class of an
address can be determined by the numerical value of the first octet.
53. Which addresses are INCORRECTLY paired with their class?
* 1 to 126, Class A
* 128 to 191, Class A
* 1 to 126, Class B
* 128 to 191, Class B
Correct answer: B & C.
Address classes are: 1 to 126, Class A; 128 to 191, Class B, 192 to 223, Class C; 224 to 239, Class D; and
54. to 255, Class E. The first octet rule states that the class of an
address can be determined by the numerical value of the first octet.
55. Which addresses are INCORRECTLY paired with their class?
* 240 – 255, Class D
* 240 – 255, Class E
* 224 – 239, Class D
* 224 – 239, Class E
Correct answer: A & D
Address classes are: 1 to 126, Class A; 128 to 191, Class B, 192 to 223, Class C; 224 to 239, Class D; and 240 to 255, Class E.
56. Which IP Address Class is INCORRECTLY paired with its range of network numbers?
* Class A addresses include 192.0.0.0 through 223.255.255.0
* Class A addresses include 1.0.0.0 through 126.0.0.0
* Class B addresses include 128.0.0.0 through 191.255.0.0
* Class C addresses include 192.0.0.0 through 223.255.255.0
* Class D addresses include 224.0.0.0 through 239.255.255.0
Correct answer: A
Class A addresses include 1.0.0.0 through 126.0.0.0
Class B addresses include 128.0.0.0 through 191.255.0.0
Class C addresses include 192.0.0.0 through 223.255.255.0
Class D addresses include 224.0.0.0 through 239.255.255.0
57. Which IP Address Class can have 16 million subnets but support 254 hosts?
* Class C
* Class A
* Class B
* Class D
Correct answer: A
Possible Subnets IP Address Class Possible Hosts
58. A 16M.
64K B 64K
16M C 254
59. Which IP Address Class can have 64,000 subnets with 64,000 hosts per subnet?
* Class B
* Class A
* Class C
* Class D
Correct answer: A
IP Address Class Possible Subnets Possible Hosts
60. A 16M
64K B 64K
16M C 254
61. There are two processes to pair MAC address with IP addresses. Which process finds an IP address from a MAC address?
* RARP
* ARP
* RIP
* IGRP
Correct answer: A
ARP (Address Resolution Protocol) maps an IP address to the MAC address,
RARP (Reverse Address Resolution Protocol) maps the MAC address to the
IP address. ARP and RARP work at the internet layer of the Internet
Model or the network layer of the OSI model.
62. When the router runs out of buffer space, this is called ________.
* Source Quench
* Redirect
* Information Request
* Low Memory
Correct answer: A
Source quench is the process where the destination router, or end
internetworking device will “quench” the date from the “source”, or the
source router. This usually happens when the destination router runs out
of buffer space to process packets.
63. Which protocol carries messages such as destination Unreachable,
Time Exceeded, Parameter Problem, Source Quench, Redirect, Echo, Echo
Reply, Timestamp, Information Request, Information Reply, Address
Request, and Address Reply?
* ICMP
* UDP
* TCP
* TFTP
* FTP
Correct answer: A
ICMP (Internet Control Message Protocol) is a network layer internet
protocol described in RFC # 792. ICMP reports IP packet information such
as destination Unreachable, Time Exceeded, Parameter Problem, Source
Quench, Redirect, Echo, Echo Reply, Timestamp, Information Request,
Information Reply, Address Request, and Address Reply.
64. Two of the protocols that can be carried in the Protocol field of an IP packet are?
* TCP
* UDP
* FTP
* TFTP
Correct answer: A & B
The following are the fields in an IP segment,
their length, and their definitions:
VERS (Version number – 16 bits)
HLEN (Number of 32-bit words in the header – 4 bits)
Type of Server (How the datagram should be handled – 32 bits)
Total Length (Total length of header and data – 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet – 6 bits)
TTL (Time-To-Live – 6 bits)
Protocol (Upperlayer protocol sending the datagram – 16 bits)
Header Checksum )Integrity check on the header – 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others – 4 bits)
Data (4 bits).
65. Where would network testing be included in an IP packet?
* IP Options field
* Identification field
* Type of Service field
* Reservation field
Correct answer: A
The following are the fields in an IP segment, their length, and their definitions:
VERS (Version number – 16 bits)
HLEN (Number of 32-bit words in the header – 4 bits)
Type of Server (How the datagram should be handled – 32 bits)
Total Length (Total length of header and data – 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet – 6 bits)
TTL (Time-To-Live – 6 bits)
Protocol (Upperlayer protocol sending the datagram – 16 bits)
Header Checksum )Integrity check on the header – 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others – 4 bits)
Data (4 bits).
66. What field tells the Internet layer how to handle an IP packet?
* Type of Service
* Identification
* Flags
* Frag Offset
Correct answer: A
The following are the fields in an IP segment, their length, and their definitions:
VERS (Version number – 16 bits)
HLEN (Number of 32-bit words in the header – 4 bits)
Type of Server (How the datagram should be handled – 32 bits)
Total Length (Total length of header and data – 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet – 6 bits)
TTL (Time-To-Live – 6 bits)
Protocol (Upperlayer protocol sending the datagram – 16 bits)
Header Checksum )Integrity check on the header – 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others – 4 bits) Data (4 bits).
67. Which fields of an IP packet provide for fragmentation of datagrams to allow differing MTUs in the internet?
* Identification
* Flags
* Frag Offset
* Type of Service
* Total Length
Correct answer: A, B & C
The following are the fields in an IP segment, their length, and their definitions:
VERS (Version number – 16 bits)
HLEN (Number of 32-bit words in the header – 4 bits)
Type of Server (How the datagram should be handled – 32 bits)
Total Length (Total length of header and data – 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet – 6 bits)
TTL (Time-To-Live – 6 bits)
Protocol (Upperlayer protocol sending the datagram – 16 bits)
Header Checksum )Integrity check on the header – 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others – 4 bits)
Data (4 bits).
68. Which processes does TCP, but not UDP, use?
* Windowing
* Acknowledgements
* Source Port
* Destination Port
Correct answer: A & B
UDP (User Datagram Protocol) does not use sequence or acknowledgement fields in transmission.
UDP is a connectionless and unreliable protocol, since there is no delivery checking mechanism in the UDP data format.
69. What is the UDP datagram format?
* Source Port – 16 bits, Destination Port – 16 bits, Length – 16 Bits, Checksum – 16 bits, Data
* Destination Port – 16 bits, Source Port – 16 bits, Length – 16 Bits, Checksum – 16 bits, Data
* Source Port – 16 bits, Destination Port – 16 bits, Checksum – 16 Bits, Length – 16 bits, Data
* Source Port – 8 bits, Destination Port – 8 bits, Length -8 Bits, Checksum – 8 bits, Data
Correct answer: A
The UDP format for a segment is as follows:
Source Port 16 bits
Destination Port 16 bits
Length 16 bits
Checksum 16 bits
Data xx bits
70. What is the function of DDR on Cisco routers?
* DDR is dial–on-demand routing. It provides a continuous LAN only connection.
* DDR is dial-on-demand routing. It provides routing for high volume traffic.
* DDR is dial–on-demand routing. It provides a continuous WAN connection.
* DDR is dial-on-demand routing. It provides routing for low volume and periodic traffic.
Correct answer: D
DDR is dial-on-demand routing. It provides routing for low volume and
periodic traffic. It initiates a call to a remote site when there is
traffic to transmit.
71. What are the two types of access lists that can be configured on a Cisco router?
* Standard
* Extended
* Filtering
* Packet
Correct answer: A & B
The access lists are standard and extended. Standard access lists for IP
check the source address of packets that could be routed. Extended
access lists can check the source and destination packet plus check for
specific protocols, port numbers, etc.
72. When using access lists, what does a Cisco router check first?
* To see if the packet is routable or bridgeable
* The destination address
* The source address
* The packet contents
Correct answer: A
The first thing checked is to see if the packet is routable or bridgeable. If it is not, the packet will be dropped.
73. How many access lists are allowed per interface?
* One per port, per protocol
* Two per port, per protocol
* Unlimited
* Router interface +1 per port.
Correct answer: A
Only one access list is allowed per interface. An access list must have
conditions that test true for all packets that use the access list.
74. What do the following commands accomplish?
access-list 1 deny 172.16.4.0 0.0.0.255
access-list 1 permit any interface ethernet 0
IP access-group 1 out
* This will block traffic from subnet 172.16.4.0 and allow all other traffic.
* This will allow traffic from subnet 172.16.4.0 and block all other traffic.
* All traffic is allowed.
* All traffic is blocked.
Correct answer: A
This will block traffic from subnet 172.16.4.0 and allow all other
traffic. The first statement “access-list 1 deny 172.16.4.0 0.0.0.255″
will deny access to the subnet 172.16.4.0.
75. What do the following statements in an extended access list accomplish?
access-list 101 deny TCP 172.16.4.0 0.0.0.255 172.16.3.0 0.0.0.255 eq 21
access-list 101 deny TCP 172.16.4.0 0.0.0.255 172.16.3.0 0.0.0.255 eq 20
access-list 101 permit TCP 172.16.4.0 0.0.0.255 0.0.0.0 255.255.255.255
* This will block ftp traffic.
* This will block http traffic.
* This will permit ftp traffic.
* This will permit tftp traffic.
Correct answer: A
This will block ftp traffic since ftp uses ports 20 and 21.
76. Access lists are numbered. Which of the following ranges could be used for an IP access list?
* 600 – 699
* 100 – 199
* 1 – 99
* 800 – 899
* 1000 – 1099
Correct answer: wer: B & C
AppleTalk access lists use numbers in the 600 – 699 range. IP uses 1 –
99 for standard access lists or 100-199 for extended access lists. IPX
uses 800 – 899 or 900 – 999 for extended access lists. IPX SAP filters
use 1000 – 1099.
77. Cisco routers use wildcard masking to identify how to check or
ignore corresponding IP address bits. What does setting a wildcard mask
bit to 0 cause the router to do?
* It tells the router to check the corresponding bit value.
* It tells the router to ignore the corresponding bit value.
* It tells the router to check its alternate routing list.
* It tells the router to use its primary routing list.
Correct answer: A
It tells the router to check the corresponding bit value.
78. You are a system administrator and you want to deny access to a
group of computers with addresses 172.30.16.0 to 172.30.31.0. Which
wildcard mask would you use?
* 0.0.15.255
* 0.0.255.255
* 0.0.31.255
* 0.0.127.255
* 0.0.255.255
Correct answer: A
0.0.15.255 will check the last 13 bits of an address so that computers
172.30.16.0 to 172.30.31.0 will be denied access. 0.0.31.255 would check
the last 6 binary digits and deny access to addresses 172.30.32.0 to
172.30.63.0. 0.0.127.255 would check the last 7 binary digits and deny
access to addresses 172.30.64.0 to 172.30.127.0. 0.0.255.255 would deny
172.30.0.0 to 172.30.254.0. If you write decimal 15 in binary, you have
0001111, the 1’s tell the router to ignore address with these bits set;
0’s tell the router to check the bits. The third octet for 172.30.16.0
is 00010000. The third octet for 172.30.31.0 would be 00011111. So,
traffic from these addresses would be denied.
79. In order to limit the quantity of numbers that a system
administrator has to enter, Cisco can use which abbreviation to indicate
0.0.0.0?
* host
* any
* all
* include
Correct answer: A
Cisco uses host to specify 0.0.0.0. This tells the router to check all.
Cisco uses any to specify 255.255.255.255. This tells the router to
ignore all and permit any address to use an access list test.
80. What do the following commands accomplish?
access-list 1 permit 172.16.0.0 0.0.255.255
interface ethernet 0
IP access-group 1 out
interface ethernet 1
IP access-group 1 out
* Only traffic from the source network 172.16.0.0 will be blocked.
* Only traffic from the source network 172.16.0.0 will be forwarded. Non-172.16.0.0 network traffic is blocked.
* Non-172.16.0.0 traffic will be forwarded.
* All traffic will be forwarded.
Correct answer: B
Only traffic from the source network 172.16.0.0 will be forwarded.
Non-172.16.0.0 network traffic is blocked. The wildcard mask 0.0.255.255
tells the router to check the first 2 octets and to ignore the last 2
octets.
81. When using access lists, it is important where those access lists
are placed. Which statement best describes access list placement?
* Put standard access lists as near the destination as possible. Put extended access lists as close to the source as possible.
* Put extended access lists as near the destination as possible. Put standard access lists as close to the source as possible.
* It isn’t import where access lists are placed since the router will read and cache the whole list.
* Put access lists as close to corporate headquarters as possible.
Correct answer: A
Put standard access lists as near the destination as possible. Put
extended access lists as close to the source as possible. Standard
access lists don’t specify the destination address.
82. As the system administrator, you enter the following commands at the command prompt:
ipx routing
access-list 800 permit 2b 4d
int e0
ipx network 4d
ipx access-group 800 out
int e1
ipx network 2b
int e2
ipx network 3c
What did these command accomplish?
* Traffic from network 4c destined for network 4d will be forwarded out Ethernet0.
* Traffic from network 3c destined for network 4d will be forwarded out Ethernet0.
* Traffic from network 2b destined for network 4d will be forwarded out Ethernet0.
* Traffic from network 4d destined for network 2d will be forwarded out Ethernet0.
Correct answer: C
Traffic from network 2b destined for network 4d will be forwarded out
Ethernet0. The other interfaces E1 and E2 are not subject to the access
list since they lack the access group statement to link them to access
list 800.
83. The following commands were entered at the command prompt of a Cisco router. What do they accomplish?
access-list 1000 deny 9e.1234.5678.1212 4
access-list 1000 permit -1
interface ethernet 0
ipx network 9e
interface ethernet 1
ipx network 4a
interface serial 0
ipx network 1
ipx output-sap-filter 1000
* File server advertisements from server 9e.1234.5678.1212 will not be forwarded on interface S0.
* All other SAP services, other than file server, from any source will be forwarded on S0.
* All other SAP services, other than print server, from any source will be forwarded on S0.
* Print server advertisements from server 9e.1234.5678.1212 will not be forwarded on interface S0.
Correct answer: A & B
File server advertisements from server 9e.1234.5678.1212 will not be
forwarded on interface S0. All other SAP services, other than file
server, from any source will be forwarded on S0.
84. You receive “input filter list is 800 and output filter list is
801″ as part of the output from a show interfaces command. What kind of
traffic are you filtering?
* IPX/SPX
* TCP/IP
* LocalTalk
* DDR
Correct answer: A
Because the access list is numbered in the 800 range, you are filtering IPX/SPX traffic.
85. Which service uses telephone control messages and signals between
the transfer points along the way to the called destination?
* Signaling System 7 (SS7)
* Time-division Multiplexing (TDM)
* X.25
* Frame relay
Correct answer: A
Signaling System 7 (SS7) uses telephone control messages and signals
between the transfer points along the way to the called destination.
Time-division Multiplexing (TDM) has information from multiple sources
and allocates bandwidth on a single media. Circuit switching uses
signaling to determine the call route, which is a dedicated path between
the sender and the receiver. Basic telephone service and Integrated
Services Digital Network (ISDN) use TDM circuits. X.25 and Frame Relay
services have information contained in packets or frames to share
non-dedicated bandwidth. X.25 avoids delays for call setup. Frame Relay
uses permanent virtual circuits (PVCs).
86. Which service takes information from multiple sources and allocates bandwidth on a single media?
* Time-division Multiplexing (TDM)
* Signaling System 7 (SS7)
* X.25
* Frame relay
Correct answer: A
87. Which three devices can be used to convert the user data from the DTE into a form acceptable to the WAN service’s facility?
* Modem
* CSU/DSU
* TA/NT1
* CO
* SS7
Correct answer: A, B & C
A modem, CSU/DSU (Channel Service Unit/Data Service Unit), or TA/NT1
(Terminal Adapter/Network Termination 1) can be used to convert the user
data from the DTE into a form acceptable to the WAN service’s facility.
88. What is the juncture at which the CPE ends and the local loop portion of the service begins?
* Demarc
* CO
* Local loop
* Last-mile
Correct answer: A
The demarcation or demarc is the juncture at which the CPE ends and the
local loop portion of the service begins. The CO (Central Office) is the
nearest point of presence for the provider’s WAN service. The local
loop or “last-mile” is the cabling that extends from the demarc into the
WAN service provider’s central office.
89. You can access three forms of WAN services with Cisco routers. Select the three forms:
* Switched or relayed services
* Interface front end to IBM enterprise data center computers
* Using protocols that connect peer-to-peer devices like HDLC or PPP encapsulation.
* IPX/SPX
* NetBEUI
Correct answer: A, B & C
You can access three forms of WAN services with Cisco routers. Switched
or relayed services include X.25, Frame Relay, and ISDN. An interface
front end to IBM enterprise data center computers includes SDLC. And,
you can access the services of WAN providers using protocols that
connect peer devices such as HDLC and PPP encapsulation. IPX/SPX and
NetBEUI are LAN protocols.
90. Select the fields for the Cisco HDLC protocol:
* Flag, Address, Control
* Flag, Address, Control, Protocol, LCP (Code, Identifier, Length, Data), FCS, Flag
* Flag, Address, Control, Data, FCS, Flag
* Flag, Address, Control, Proprietary, Data, FCS, Flag
Correct answer: D
The Cisco HDLC frame format is Flag, Address, Control Proprietary, Data,
FCS, Flag. The PPP frame format is Flag, Address, Control, Protocol,
LCP (Code, Identifier, Length, Data), FCS, Flag. The SDLC and LAPB
format is Flag, Address, Control, Data, FCS, Flag.
85: Select the physical interfaces that PPP can be configured on a Cisco router:
* Asynchronous serial
* HSSI
* ISDN
* Synchronous serial
Correct answer: A, B, C & D
All four of them can carry PPP traffic. HSSI is High Speed Serial Interface.
91. Select the correct statements about PPP and SLIP for WAN communications?
* PPP uses its Network Control Programs (NCPs) component to encapsulate multiple protocols.
* PPP can only transport TCP/IP
* SLIP can only transport TCP/IP.
* SLIP uses its Network Control Programs (NCPs) component to encapsulate multiple protocols.
Correct answer: A & C
87a Which protocol for PPP LCP (Link Control Protocol) performs a challenge handshake?
* CHAP
* PAP
* UDP
* IPX
Correct answer: A
87b Which form of PPP error detection on Cisco routers monitors data dropped on a link?
* Quality
* Magic Number
* Error Monitor
* Droplink
Correct answer: A
The Quality protocol monitors data dropped on a link. Magic Number avoids frame looping.
92. Which protocol for PPP provides load balancing across multiple links?
* Multilink Protocol (MP)
* Quality
* Magic Number
* Stacker
* Predictor
Correct answer: A
93. As the system administrator, you type “ppp authentication chap
pap secret”. Which authentication method is used first in setting up a
session?
* secret
* PAP
* CHAP
* PPP/SLIP
Correct answer: C
94. Select the compression protocols for PPP?
* Stac
* Predictor
* Quality
* Magic Number
Correct answer: A & B
95. What are the three phases of PPP session establishment?
* Link establishment phase
* Authentication phase
* Network layer protocol phase
* Handshake phase
* Dial-in phase
Correct answer: A, B & C
96. What is the default IPX Ethernet encapsulation?
* SNAP
* Arpa
* 802.2
* Novell-Ether
* SAP
Correct answer: D
97. What must be true for two Routers running IGRP to communicate their routes?
* Same autonomous system number
* Connected using Ethernet only
* Use composite metric
D)Configured for PPP
Correct answer: A
98. The following is partial output from a routing table, identify
the 2 numbers in the square brackets; ‘192.168.10.0 [100/1300] via
10.1.0.1, 00:00:23, Ethernet1′
* 100 = metric, 1300 = administrative distance
* 100 = administrative distance, 1300 = hop count
* 100 = administrative distance, 1300 = metric
* 100 = hop count, 1300 = metric
Correct answer: C
99. Identify 3 methods used to prevent routing loops?
* Split horizon
* Holddown timers
* Poison reverse
* SPF algorithm
* LSP’s
Correct answer: A B C
100. Which statement is true regarding full duplex?
* Allows for transmission and receiving of data simultaneously
* Only works in a multipoint configuration
* Does not affect the bandwidth
* Allows for transmission and receiving of data but not a the same time
Correct answer: A
Full duplex is just the opposite of half duplex. It handles traffic in both directions simultaneously.
Following are the key points to remember for RAID level 1.
