Tag - MAC address

1
Basic CCNA Job Interview Questions
2
Switching Question updated
3
CCNA Switching Dumps
4
Short Question CCNA Part 7
5
CCNA Interview Questions

Basic CCNA Job Interview Questions

1: What is unicast and how does it work?

Unicast is a one-to-one transmission method. A single frame is sent from the
source to a destination on a network. When this frame is received by the switch,
the frame is sent on to the network, and the network passes the frame to its
destination from the source to a specific destination on a network.

ccna interview questions

2: What is multicast and how does it work?

** Multicast is a one-to-many transmission method. A single frame is sent from
the source to multiple destinations on a network using a multicast address. When
this frame is received by the switch, the frame is sent on to the network and the
network passes the frame to its intended destination group.

3:  What is broadcast and how does it work?

** Broadcast is a one-to-all transmission method. A single frame is sent from the
source to a destination on a network using a multicast address. When this frame
is received by the switch, the frame is sent on to the network. The network
passes the frame to all nodes in the destination network from the source to an
unknown destination on a network using a broadcast address. When the switch
receives this frame, the frame is sent on to all the networks, and the networks
pass the frame on to all the nodes. If it reaches a router, the broadcast frame is
dropped.

4: What is fragmentation?

** Fragmentation in a network is the breaking down of a data packet into smaller
pieces to accommodate the maximum transmission unit (MTU) of the network.

5: What is MTU? What’s the MTU for traditional Ethernet?

** MTU is the acronym for maximum transmission unit and is the largest frame
size that can be transmitted over a network. Messages longer than the MTU
must be divided into smaller frames. The network layer (Layer 3) protocol
determines the MTU from the data link layer (Layer 2) protocol and fragments the
messages into the appropriate frame size, making the frames available to the
lower layer for transmission without further fragmentation. The MTU for Ethernet
is 1518 bytes.

6: What is a MAC address?

** A MAC address is the physical address of a network device and is 48 bits (6
bytes) long. MAC addresses are also known as physical addresses or hardware
addresses.

7:  What is the difference between a runt and a giant, specific to traditional
Ethernet?

** In Ethernet a runt is a frame that is less than 64 bytes in length, and a giant is
a frame that is greater than 1518 bytes in length. Giants are frames that are
greater than the MTU used, which might not always be 1518 bytes.

8: What is the difference between store-and-forward and cut-through
switching?

** Cut-through switching examines just the frame header, determining the output
switch port through which the frame will be forwarded. Store-and-forward
examines the entire frame, header and data payload, for errors. If the frame is
error free, it is forwarded out its destination switch port interface. If the frame has
errors, the switch drops the frame from its buffers. This is also known as
discarding the frame to the bit bucket.

9: What is the difference between Layer 2 switching and Layer 3 switching?

* * Layer 2 switches make their forwarding decisions based on the Layer 2 (data
link) address, such as the MAC address. Layer 3 switches make their forwarding
decisions based on the Layer 3 (network) address.

10: What is the difference between Layer 3 switching and routing?

** The difference between Layer 3 switching and routing is that Layer 3 switches
have hardware to pass data traffic as fast as Layer 2 switches. However, Layer 3
switches make decisions regarding how to transmit traffic at Layer 3 in the same
way as a router. A Layer 3 switch cannot use WAN circuits or use routing
protocols; a router is still required for these functions.

Back

Switching Question updated

Question 9

A network administrator needs to configure port security on a switch. Which two statements are true? (Choose two)

A. The network administrator can apply port security to dynamic access ports
B. The network administrator can configure static secure or sticky secure mac addresses in the voice vlan.
C. The sticky learning feature allows the addition of dynamically learned addresses to the running configuration.
D. The network administrator can apply port security to EtherChannels.
E. When dynamic mac address learning is enabled on an interface, the switch can learn new addresses up to the maximum defined.

 

Answer: C E

Question 10

Refer to the exhibit. Which statement is true?

 

 

 

 

 

 

 

 

 

 

 

A. The Fa0/11 role confirms that SwitchA is the root bridge for VLAN 20.
B. VLAN 20 is running the Per VLAN Spanning Tree Protocol.
C. The MAC address of the root bridge is 0017.596d.1580.
D. SwitchA is not the root bridge, because not all of the interface roles are designated.

 

Answer: D

Explanation

Only non-root bridge can have root port. Fa0/11 is the root port so we can confirm this switch is not the root bridge -> A is not correct.

From the output we learn this switch is running Rapid STP, not PVST -> B is not correct.

0017.596d.1580 is the MAC address of this switch, not of the root bridge. The MAC address of the root bridge is 0017.596d.2a00 -> C is not correct.

All of the interface roles of the root bridge are designated. SwitchA has one Root port and 1 Alternative port so it is not the root bridge -> D is correct.

Question 12

A network administrator wants to ensure that only the server can connect to port Fa0/1 on a Catalyst switch. The server is plugged into the switch Fa0/1 port and the network administrator is about to bring the server online. What can the administrator do to ensure that only the MAC address of the server is allowed by switch port Fa0/1? (Choose two)

A. Configure port Fa0/1 to accept connections only from the static IP address of the server.
B. Employ a proprietary connector type on Fa0/1 that is incompatible with other host connectors.
C. Configure the MAC address of the server as a static entry associated with port Fa0/1.
D. Bind the IP address of the sewer to its MAC address on the switch to prevent other hosts from spoofing the server IP address.
E. Configure port security on Fa0/1 to reject traffic with a source MAC address other than that of the server.
F. Configure an access list on the switch to deny server traffic from entering any port other than Fa0/1.

 

Answer: C E

Explanation

We can”configure the MAC address of the server as a static entry associated with port Fa0/1″ with this command:

Switch(config-if)#switchport port-security mac-address sticky 0000.00AA.AAAA.AAAA

and “configure port security on Fa0/1 to reject traffic with a source MAC address other than that of the server” with these commands:

Switch(config-if)#switchport port-security maximum 1 (only allow 1 MAC address and that is the static MAC address)

Also we often define what will the switch do if the security is violated:

Switch(config-if)#switchport port-security violation shutdown

Question 13

The network security policy requires that only one host be permitted to attach dynamically to each switch interface. If that policy is violated, the interface should shut down. Which two commands must the network administrator configure on the 2950 Catalyst switch to meet this policy? (Choose two)

A. Switch1(config-if)#switchport port-security maximum 1
B. Switch1(config)#mac-address-table secure
C. Switch1(config)#access-list 10 permit ip host
D. Switch1(config-if)#switchport port-security violation shutdown
E. Switch1(config-if)#ip access-group 10

 

Answer: A D

 

Question 1

In which circumstance are multiple copies of the same unicast frame likely to be transmitted in a switched LAN?

A. after broken links are re-established
B. in an improperly implemented redundant topology
C. when upper-layer protocols require high reliability
D. during high traffic periods
E. when a dual ring topology is in use

 

Answer: B

Explanation

If we connect two switches via 2 or more links and do not enable STP on these switches then a loop (which creates multiple copies of the same unicast frame) will occur. It is an example of an improperly implemented redundant topology.

Question 2

An administrator would like to configure a switch over a virtual terminal connection from locations outside of the local LAN. Which of the following are required in order for the switch to be configured from a remote location? (Choose two)

A. The switch must be configured with an IP address, subnet mask, and default gateway.
B. The switch must be connected to a router over a VLAN trunk.
C. The switch must be reachable through a port connected to its management VLAN.
D. The switch console port must be connected to the Ethernet LAN.
E. The switch management VLAN must be created and have a membership of at least one switch port.
F. The switch must be fully configured as an SNMP agent.

 

Answer: A C

Explanation

In order to remote access to a switch from outside of the local LAN (in a different subnet) we have to:

+ Configure an IP address on a VLAN on that switch, this VLAN is known as the management VLAN (it is usually VLAN 1)
+ Specify the default gateway for that switch so that it can send traffic to this gateway

Below shows an example of configuring remote access for a switch (suppose the management VLAN on the switch is 192.168.1.10/24 and the default-gateway IP address is 192.168.1.254)

Switch(config)#ip default-gateway 192.168.1.254
Switch(config)#interface vlan 1
Switch(config)#ip address 192.168.1.10 255.255.255.0
Switch(config)#no shutdown

Question 3

Refer to the exhibit. A junior network administrator was given the task of configuring port security on SwitchA to allow only PC_A to access the switched network through port fa0/1. If any other device is detected, the port is to drop frames from this device. The administrator configured the interface and tested it with successful pings from PC_A to RouterA, and then observes the output from these two show commands.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Which two of these changes are necessary for SwitchA to meet the requirements? (Choose two)

A. Port security needs to be globally enabled.
B. Port security needs to be enabled on the interface.
C. Port security needs to be configured to shut down the interface in the event of a violation.
D. Port security needs to be configured to allow only one learned MAC address.
E. Port security interface counters need to be cleared before using the show command.
F. The port security configuration needs to be saved to NVRAM before it can become active.

 

Answer: B D

Explanation

As we see in the output, the “Port Security” is in “Disabled” state (line 2 in the output). To enable Port security feature, we must enable it on that interface first with the command:

SwitchA(config-if)#switchport port-security

-> B is correct.

Also from the output, we learn that the switch is allowing 2 devices to connect to it (switchport port-security maximum 2) but the question requires allowing only PC_A to access the network so we need to reduce the maximum number to 1 -> D is correct.

Question 4

A company implements video conferencing over IP on their Ethernet LAN. The users notice that the network slows down, and the video either stutters or foils completely. What is the most likely reason for this?

A. minimum cell rate (MCR)
B. quality of service (QoS)
C. modulation
D. packet switching exchange (PSE)
E. reliable transport protocol (RTP)

 

Answer: B

Explanation

If the QoS is not configured correctly on the network (for example configure your network’s bandwidth below the bandwidth assigned by your ISP) can slow down all your traffic.

Question 8

Refer to the exhibit. Some 2950 series switches are connected to the conference area of the corporate headquarters network. The switches provide two to three jacks per conference room to host laptop connections for employees who visit the headquarters office. When large groups of employees come from other locations, the network administrator often finds that hubs have been connected to wall jacks in the conference area although the ports on the access layer switches were not intended to support multiple workstations.

What action could the network administrator take to prevent access by multiple laptops through a single switch port and still leave the switch functional for its intended use?

 

 

 

 

 

 

 

 

 

 

 

 

A. Configure static entries in the switch MAC address table to include the range of addresses used by visiting employees.
B. Configure an ACL to allow only a single MAC address to connect to the switch at one time.
C. Use the mac-address-table 1 global configuration command to limit each port to one source MAC address.
D. Implement Port Security on all interfaces and use the port-security maximum 1 command to limit port access to a single MAC address
E. Implement Port Security on all interfaces and use the port-security mac-address sticky command to limit access to a single MAC address
F. Implement Port Security at global configuration mode and use the port-security maximum 1 command to allow each switch only one attached hub

 

Answer: D

Explanation

The Port Security filters frames based on its MAC so it can effectively prevent people connecting to the switch via hubs.

Question 9

Which of the following statements are true regarding bridges and switches? (Choose 3)

A. Switches are primarily software based while bridges are hardware based.
B. Both bridges and switches forward Layer 2 broadcasts.
C. Bridges are frequently faster than switches.
D. Switches have a higher number of ports than most bridges.
E. Bridges define broadcast domains while switches define collision domains.
F. Both bridges and switches make forwarding decisions based on Layer 2 addresses.

 

Answer: B D F

Question 10

A network administrator must configure 200 switch ports to accept traffic from only the currently attached host devices. What would be the most efficient way to configure MAC-level security on all these ports?

A. Visually verify the MAC addresses and then telnet to the switches to enter the switchport-port security mac-address command.
B. Have end users e-mail their MAC addresses. Telnet to the switch to enter the switchport-port security mac-address command.
C. Use the switchport port-security MAC address sticky command on all the switch ports that have end devices connected to them.
D. Use show mac-address-table to determine the addresses that are associated with each port and then enter the commands on each switch for MAC address port-security.

 

Answer: C

Explanation

We can use the “interface range” command (for example “interface range FastEthernet 0/1 – 48″) to configure many ports as the same time and use the “port-security MAC address sticky” command (without a specific MAC address) to dynamically learn the attached MAC Address and place it into the switch’s running-configuration -> C is correct.

Which two of these changes are necessary for SwitchA to meet the requirements? (Choose two)

A. Port security needs to be globally enabled.
B. Port security needs to be enabled on the interface.
C. Port security needs to be configured to shut down the interface in the event of a violation.
D. Port security needs to be configured to allow only one learned MAC address.
E. Port security interface counters need to be cleared before using the show command.
F. The port security configuration needs to be saved to NVRAM before it can become active.

 

Answer: B D

Explanation

As we see in the output, the “Port Security” is in “Disabled” state (line 2 in the output). To enable Port security feature, we must enable it on that interface first with the command:

SwitchA(config-if)#switchport port-security

-> B is correct.

Also from the output, we learn that the switch is allowing 2 devices to connect to it (switchport port-security maximum 2) but the question requires allowing only PC_A to access the network so we need to reduce the maximum number to 1 -> D is correct.

Question 4

A company implements video conferencing over IP on their Ethernet LAN. The users notice that the network slows down, and the video either stutters or foils completely. What is the most likely reason for this?

A. minimum cell rate (MCR)
B. quality of service (QoS)
C. modulation
D. packet switching exchange (PSE)
E. reliable transport protocol (RTP)

 

Answer: B

Explanation

If the QoS is not configured correctly on the network (for example configure your network’s bandwidth below the bandwidth assigned by your ISP) can slow down all your traffic.

CCNA Switching Dumps

Question 1

Refer to the exhibit. The following commands are executed on interface fa0/1 of 2950Switch.

2950Switch(config-if)#switchport port-security
2950Switch(config-if)#switchport port-security mac-address sticky
2950Switch(config-if)#switchport port-security maximum 1

The Ethernet frame that is shown arrives on interface fa0/1. What two functions will occur when this frame is received by 2950Switch? (Choose two)

 

 

 

 

 

 

 

 

 

 

 

A. The MAC address table will now have an additional entry of fa0/1 FFFF.FFFF.FFFF.
B. Only host A will be allowed to transmit frames on fa0/1.
C. This frame will be discarded when it is received by 2950Switch.
D. All frames arriving on 2950Switch with a destination of 0000.00aa.aaaa will be forwarded out fa0/1.
E. Hosts B and C may forward frames out fa0/1 but frames arriving from other switches will not be forwarded out fa0/1.
F. Only frames from source 0000.00bb.bbbb, the first learned MAC address of 2950Switch, will be forwarded out fa0/1.

Answer: B D

Explanation

Please read the explanation at http://www.9tut.net/icnd2/icnd2-operations

Question 2

Which Cisco Catalyst feature automatically disables the port in an operational PortFast upon receipt of a BPDU?

A. BackboneFast
B. UplinkFast
C. Root Guard
D. BPDU Guard
E. BPDU Filter

 

Answer: D

Explanation

We only enable PortFast feature on access ports (ports connected to end stations). But if someone does not know he can accidentally plug that port to another switch and a loop may occur when BPDUs are being transmitted and received on these ports.

With BPDU Guard, when a PortFast receives a BPDU, it will be shut down to prevent a loop -> D is correct.

Question 3

Why will a switch never learn a broadcast address?

A. Broadcast frames are never sent to switches.
B. Broadcast addresses use an incorrect format for the switching table.
C. A broadcast address will never be the source address of a frame.
D. Broadcasts only use network layer addressing.
E. A broadcast frame is never forwarded by a switch.

 

Answer: C

Question 4

Which three statements accurately describe layer 2 Ethernet switches? (choose three)

A. Microsegmentation decreases the number of collisions on the network.
B. If a switch receives a frame for an unknown destination.it uses ARP to resolve the address.
C. Spanning Tree Protocol allows switches to automatically share vlan information.
D. In a property functioning network with redundant switched paths, each switched segment will contain one root bridge with all its ports in the forwarding state. All other switches in that broadcast domain will have only one root port.
E. Establishing vlans increases the number of broadcast domains.
F. Switches that are configured with vlans make forwarding decisions based on both layer 2 and layer 3 address information.

 

Answer: A D E

Question 5

Switch ports operating in which two roles will forward traffic according to the IEEE 802.1w standard? (Choose two)

A. alternate
B. backup
C. designated
D. disabled
E. root

 

Answer: C E

Explanation

IEEE 802.1w is the standard of Rapid Spanning Tree Protocol (RSTP). There are 5 port roles in this standard: Root port, Designated port, Alternative port, Backup port and Disabled port. In these 5 port roles, only Root port and Designated port can forward traffic.

Question 6

Select the action that results from executing these commands:

Switch(config-if)# switchport port-security
Switch(config-if)# switchport port-security mac-address sticky

A. A dynamically learned MAC address is saved in the startup-configuration file.
B. A dynamically learned MAC address is saved in the running-configuration file.
C. A dynamically learned MAC address is saved in the VLAN database.
D. Statically configured MAC addresses are saved in the startup-configuration file if frames from that address are received.
E. Statically configured MAC addresses are saved in the running-configuration file if frames from that address are received.

 

Answer: B

Explanation

The full syntax of the second command is:

switchport port-security mac-address sticky [MAC]

If we don’t specify the MAC address (like in this question) then the switch will dynamically learn the attached MAC Address and place it into your running-configuration -> B is correct.

Question 7

What is valid reason for a switch to deny port access to new devices when port security is enabled?

A. The denied MAC addresses have already been learned or configured on another secure interface in the same VLAN.
B. The denied MAC address are statically configured on the port.
C. The minimum MAC threshold has been reached.
D. The absolute aging times for the denied MAC addresses have expired.

 

Answer: A

Explanation

A security violation occurs in either of these situations:

* When the maximum number of secure MAC addresses is reached on a secure port and the source MAC address of the ingress traffic is different from any of the identified secure MAC addresses, port security applies the configured violation mode.

* If traffic with a secure MAC address that is configured or learned on one secure port attempts to access another secure port in the same VLAN, applies the configured violation mode.

From the second statement we can figure out A is the correct answer. But for your information we will discuss other answers as well.

Answer B is not correct because we can’t configured which MAC address will be denied. We can only configure which MAC is allowed.

We can only configure the maximum MAC threshold, not the minimum threshold -> C is not correct.

The aging times are only configured for allowed MAC addresses, not for denied MAC -> D is correct.

For your information about aging time:

When the aging type is configured with the absolute keyword, all the dynamically learned secure addresses age out when the aging time expires

This is how to configure the secure MAC address aging type on the port:

Router(config-if)# switchport port-security aging type absolute

and configure the aging time (aging time = 120 minutes)

Router(config-if)# switchport port-security aging time 120

When this command is used, all the dynamically learned secure addresses age out when the aging time expires

(Reference: http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/port_sec.html)

 

Short Question CCNA Part 7

63 – What we called 64 Bit Mac-address in IPV6?

EUI= Enhanced universal identifier – 16 bits add in IPv6 so it’s called EUI

64 – What is loop back IP in IPV6?

::1 and ping 6

65- Which command we use for ping in IPv6?

Ping6 source IP -s Destination IP

66- How many types of router?

Two types

i) Modular

ii) Non-Modular

67- When we use Router?

For communication between different networks

68- Which works router Do ?

1- Path selection and

2- Packet Switching {frame relay}

69 – What cable called V.35 ?

Serial Connectivity cable

70- How many types of Ethernet?

4 types

i) Ethernet

ii) Fast Ethernet

iii) Gigabit

iv) 10 Giga.

71 – Which cable called roll-over?

Console access able

72- Which cable we connect in DB-9 ?

Roll over calbe

73- How many ways to access router?

3 ways

i) Telnet (IP)

ii) AUX (Telephone)

iii) Console (cable)

74- What is IOS?

Internet Operating system. Its router’s operating system.

75 – In which IOS version 182 people can access router through telenet ?

Onward 12.2 version

76- Which mode called privilege mode?

Second mode

77- When we use interface mode?

For specific interface commands

78- On Which mode we give debug command?

Privilege mode / live view (2nd mode)

 

79- Which command we give on privilege mode for coming back to user execution mode?

Disable

80- Which mode we can’t skip when we come back from interface mode?

2nd mode we can’t skip

CCNA Interview Question Part 1

CCNA Interview Question Part 2

CCNA Interview Question Part 3

CCNA Interview Question Part 4

CCNA Interview Question Part 5

CCNA Interview Question Part 6

CCNA Interview Question Part 7

CCNA Interview Question Part 8

CCNA Interview Question Part 9

CCNA Interview Question Part 10

CCNA Interview Question Part 11

CCNA Interview Question Part 12

CCNA Interview Question Part 13

CCNA Interview Question Part 14

CCNA Interview Questions

After Review CCNA course we Conclude some short Questions with Answers

CCNA Interview Question Part 1

CCNA Interview Question Part 2

CCNA Interview Question Part 3

CCNA Interview Question Part 4

CCNA Interview Question Part 5

CCNA Interview Question Part 6

CCNA Interview Question Part 7

CCNA Interview Question Part 8

CCNA Interview Question Part 9

CCNA Interview Question Part 10

CCNA Interview Question Part 11

CCNA Interview Question Part 12

CCNA Interview Question Part 13

CCNA Interview Question Part 14

Copyright © 2024. Created by IT Learning. Powered by DumpsForAll | Terms of Use | Privacy Policy