Archivio mensile:agosto 2012

CCNA Exam Q & A (Volume B)

Question 1 :

Which two of these statements are true of IPv6 address representation ? (Choose two)

A – There are four types of IPv6 addresses : unicast, anycast, multicast and broadcast

B – A single interface may be assigned multiple IPv6 addresses of any type

C – Every IPv6 interface contains at least one loopback address

D – The first 64 bits represents the dynamically created interface ID

E – Leading Zeros in an IPv6 16 bit hexadecimal field are mandatory

Answer : B, C

Question 2 :

What is the name of the VTP mode of operation that enables a switch to forward only VTP advertisements while sitll permitting the editing of local VLAN  information ?

A – Server

B – Client

C – Tunnel

D – Transparent

Answer : D

Question 3 :

Which of the following describes the roles of devices in a WAN ? (Choose three)

A – A CSU/DSU terminates a digital local loop

B – A modem terminates a digital local loop

C – A CSU/DSU terminates an analog local loop

D – A modem terminates an analog local loop

E – A router is commonly considered a DTE Device

F – A router is commonly considered a DCE Device

Answer : A, D, E

Question 4 :

Cisco Catalyst Switches CAT1 and CAT2 have a connection between them using ports Fa0/13. An 802.1Q trunk is configured between the two switches. On CAT1, VLAN 10 is chosen as native, but on CAT2 the native VLAN is not specified.

What will happen in this scenario ?

A – 802.1Q giants frames could saturate the link

B – VLAN 10 on CAT1 and VLAN1 on CAT2 will send untagged frames

C – A native VLAN mismatch error message will appear

D – VLAN 10 on CAT1 and VLAN1 on CAT2 will send tagged frames

Answer : C

Question 5 :

Which network protocol does DNS use ?






Answer : D

Question 6 :

What is the first 24 bits in a MAC address called ?





Answer : C

Explanation :

The MAC address is expressed as a 48-bit hexadecimal number. The first 24 – bit number is to identify the Vendor/Manufacturer, also called OUI. The latter 24-bit is assigned by the vendor.

Question 7 :

Refer to the exhibit. The router has  been configured with these commands :

hostname Gateway

interface FastEthernet 0/0

ip address

no shutdown

interface FastEthernet 0/1

ip address

no shutdown

interface serial 0/0

ip address

no shutdown

ip route

What are the two results of this configuration ? (Choose two)

A – The Default route should have a next hop address of

B – Hosts on the LAN that is connected to FastEthernet 0/1 are using public IP addressing

C – The Address of the subnet segment with the WWW server will support seven more servers

D – The addressing scheme allows users on the internet to access the WWW server

E – Hosts on the LAN that is connected to FastEthernet 0/1 will not be able to access the internet without address translation.

Answer : D, E

Explanation :

Since the hosts on the FastEthernet 0/1 network are using private IP addressing their IP addresses will need to be translated into a publicly routable address in order to access the internet.

The Server is using a public IP address so internet users can indeed access this server.

Question 8 : 

Which statement about IPv6 is true ?

A – Addresses are not hierachical and are assigned at random .

B – Only one IPv6 address can exist on a given interface.

C – There are 2.7 billion addresses available.

D – Broadcasts have been eliminated and replaced with multicasts.

Answer : D

Question 9 :

On the network, what is the last IP address that can be assigned to a host ?

A –

B –

C –

D –

Answer : A

Question 10 :

Which Switch would STP choose to become the root bridge in the selection process ?

A – 32768: 11-22-33-44-55-66

B – 32768: 22-33-44-55-66-77

C – 32769: 11-22-33-44-55-65

D – 32769: 22-33-44-55-66-78

Answer : A

Question 11 : 

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

A – Configure port security to shut down the interface in the event of a violation

B – Port Security needs to be enabled on the interface

C – Enable port security globaly

D – Port security needs to be configured to allow only one learned MAC address

Answer : B, D

Question 12 : 

Before installing a new, upgraded version of the IOS, what should be checked on the router, and which command should be used to gather this information ? (Choose two)

A – the amount of available ROM

B – the amount of available flash and RAM memory

C – the version of the bootstrap software present on the router

D – show version

E – show processes

F – show running-config

Answer : B, D

Question 13 :

How many bits are contained in each filed of an IPv6 address ?

A – 24

B – 4

C – 8

D – 16

Answer : D

Question 14 :

On the basis  of the IEEE 802.1w standard, which two switch ports can forward traffic ?

A – Alternate

B – Backup

C – Designated

D – Disabled

E – Root

Answer : C, E


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Pubblicato da su agosto 26, 2012 in Networking


CCNA Exam Q & A (Volume A)

Question 1 :
Refer to the ehibit. Assume that the routing protocol referenced in each choice below is configured with its default settings and the given routing protocol is running on all the routers. Which two conditional statements accurately state the patt that will be chosen between networks and for the routing protcol mentioned ? (choose two)

A – if  OSPF is the routing protocol, the path will be from R1 to R3 to R4 to R5.

B – if OSPF is the routing protocol, the path will be from R1 to R2 to R5

C – if OSPF is the routing protocol , the path will be from R1 to R5

D – if RIPv2 is the routing protocol, the path will be from R 1 to R3 to R4 to R5.

E – if RIPv2 is the routing protocol, the path will be from R1 to R5.

Answer : A, E

Question 2 :

QoS policies are applied on the switches of a LAN. Which type of command will show the effects of the policy in real time ?

A – Show Command

B – debug Command

C – configuration Command

D – rommon Command

Answer : B

Question 3 :

Which two benefits are provided by creating VLANs ? (Choose two)

A – added security

B – dedicated bandwidth

C – provides segmentation

D – allows switches to route traffic between subinterfaces

E – contains collisions

Answer : A,C

Question 4 :

Which two security appliances will you use in a network ? (Choose two)


B – ids

C – ios

D – iox

E – ips


Answer : B,E

Question 5 :

Hosts one the same VLAN can communicate with each other but are unable to communicate with hosts on different VLANs. What is needed to allow communication between VLANs ?

A – a router with an IP address on the physical interface that is connected to the Switch.

B – a router with subinterfaces configured on the physical interface that is connected to the switch

C – a switch with an access link that is configured between the switches

D – a switch with a trunk link that is configured between the switches

Answer : B

Explanation :

Different VLANs can’t communicate with each other, the can communicate with the help of Layer3 router, Hence, it is needed to connect a router to a switch, then make the sub-interface on the router to connect to the switch, establishing Trunking links to achieve communications of devices which belongs to different VLANs.

Question 6 :

Which port state is introduced by Rapid-PVST ?

A – Learning

B – Listening

C – Discarding

D – Forwarding

Answer : C

Question 7 :

Which two descriptions are correct about characteristics of IPv6 unicast addressing ? (Choose two)

A – Global addresses start with 2000::/3.

B – Link-local addresses start with FE00:/12.

C – Link – local addresses start with FF00::/10.

D – There is only one loopback address and it is ::1.

E – if a global address is assigned to an interface , then that is only allowable address for the interface.

Answer : A,D

Question 8 :

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 interce roles are designated.

Answer : D

Question 9 :

Which two devices can interfere with the operationg of a wireless network because they operate on similare frequencies ? (Choose two)

A – toaster

B – IP phone

C – AM radio

D – cordless phone

E – microware oven

F – copier

Answer : D,E


The Microwave and Cordless phone in the 2.4GHZ spectrum band will interfere with the operation of a wireless network.

Question 10 :

What are three basic parameters to configure on a wireless access point ? (Choose three)





E – RF Channel

F – Authentication method

Answer : A, E, F

Question 11 :

Which option is a valid IPv6 address ?

A – 2001:0000:130F::099a::12a

B – 2002:7654:A1AD:61:81AF:CCC1

C – FEC0:ABCD:WYZ:0067::2A4

D – 2004:1:25A4:886F::1

Answer : D

Question 12 :

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

Question 13 :

For which type of connection should a straight-though cable be used ?

A – Switch to Switch

B – Switch to Hup

C – Switch to Router

D – hub to hub

E – router to PC

Answer : C

Question 14 :

Refer to the exhibut. What two facts can be determined from the WLAN diagram ? (Choose two)

A – The Area of overlap of the two cells represents a basic service set (BSS)

B – The network diagram represents an extended service set (ESS)

C – Access points in each cell must be configured to use channel 1

D – The area overlap must be less than 10% of the area to ensure connectivity

E – The two APs should be configued to operate on different channels

Answer : B, E 

Question 15 :

Refer to the exhibit. A network administrator is adding two new hosts to SwitchA. Which three values could be used for the configuration of these hosts ? (Choose three)

A – host A IP address :

B – host A IP address :

C – host A default gateway

D – host B IP address :

E – host B default gateway :

F – host B IP address :

Answer : A, C, F

Question 16 :

Which type of cable is used to connect the COM port of a host to the COM port of a router or switch ?

A – crossover

B – straight-through

C – rolled

D – shielded twisted-pair

Answer : C

Question 17 :

Refer to the exhibit, Which two statements are true about the loopback address that is configured on Router B ? (Choose two)

A – It ensures that data will be forwarded by RouterB

B – It provides stability for the OSPF process on RouterB

C – It specifies that the router ID for RouterB should be

D – It decreases the metric for routes that are advertised from RouterB

E – It indicates that RouterB should be elected the DR for the LAN.

Answer : B, C

Question 18 :

Where does the routing occur within the DoD TCP/IP reference model ?

A – application

B – internet

C – network

D – transport

Answer : B


This question is to examine the TCP/Ip model.

TCP/IP model has four layers: Process/Application layer, Host-to-Host layer, internet layer, Network access layer.

Routing occurs at the internet layer.

Question 19 :

Refer to the exhibit. This command is executed on 2960Switch:

2960Switch(config)#mac-address-table static 0000.00aa.aaaa vlan 10 interface fa0/1

A – Port security is implemented on the fa0/1 interface

B – MAC address 0000.00aa.aaaa does not need to be learned by this Switch

C – Only MAC address 0000.00aa.aaaa can source frames on the fa0/1 segment

D – Frames with layer 2 source address 0000.00aa.aaaa will be forwarded out fa0/1

E – MAC address 0000.00aa.aaaa will be listed in the MAC address table for interface fa0/1 only

Answer : B, E

Question 20 :

Which two link protcols are used to carry multiple VLANs over a single link ? (Choose two)


B – 802.1q


D – isl

E – 802.3u

Answer: B, D

Explanation :

This question is to check the trunking protocol.

IGP is an interior gateway protocol and also a routing protocol, such as OSPF  and EIGRP

802.1 q and isl are trunking protocols which can be used to carry the traffic of multiple VLANs over a sing link. ISL is a Cisco proprietary protocol.

802.3u (100Base- T) is 100 Mbps Ethernet standard


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Pubblicato da su agosto 26, 2012 in Networking


Split Horizon !!

In this example, network node A routes packets to node B in order to reach node C. The links between the nodes are distinct point-to-point links.

According to the split-horizon rule, node A does not advertise its route for C (namely A to B to C) back to B. On the surface, this seems redundant since B will never route via node A because the route costs more than the direct route from B to C. However, if the link between B and C goes down, and B had received a route from A, B could end up using that route via A. A would send the packet right back to B, creating a loop. With the split-horizon rule in place, this particular loop scenario cannot happen, improving convergence time in complex,highly-redundant environments.


There are scenarios where the split-horizon rule may fail. Suppose 6 nodes(A,B,C,D,E,F) are each connected to every other node. The lowest cost routes will establish over time. Now if one of the nodes fails. Split-horizon only protects each node from where their current path is received from. But the same information received from the other nodes will be transmitted as well.


If A connects to E via B and C. And if D connects to E via A->B->C. Suppose B-C fail. A will not advertise its route to E to B directly due to the split-horizon rule. However, as each node is connected to each other. D will advertise the route to E to B (D->A->B->C-E). The split horizon rule stops D from advertising the route to A. Not to B.


Such scenarios and multiple links exist in practical networks. And it is the network administrator who needs to work out such intricacies.




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Pubblicato da su agosto 20, 2012 in Networking


Floating Static Route !

By Default, a static route will always be used instead of a routing protocol, By adding an AD (Administrative Distance) number to your ip route statement.

if your network is using EIGRP, and you need a backup route, add a static route with an AD greater than 90.

EIGRP will be used because its AD is better (lower) than the static route.

But if EIGRP goes down, the static route will be used in its place. This is known as a floating static route.

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Pubblicato da su agosto 20, 2012 in Networking


What is Cloud Computing ??

Cloud computing is the use of computing resources (hardware and software) that are delivered as a service over a netowrk (typically the Internet). The name comes from the use of a cloud-shaped symbol as an abstraction for the complex infrastructure it contains in system diagrams. Cloud computing entrusts remote services with a user’s data, software and computation.

Cloud computing in turn is computing which leverages the internet as a tool through which remote computers share memory, processing, network capacity, software, and other IT services on-demand.

The Cloud Pyramid :
The basic architecture of the Cloud is simple and is called the “Cloud Pyramid,” the resources of the Cloud can be visualized as three key segments: Cloud infrastructure at the bottom, Cloud platforms in the middle, and Cloud applications at the top.
– Apps
– Platform
– Infrastructure

At the apps level of a Cloud, client enterprises are served fully functioning Software as a Service (SaaS) resources, with little need for programming on the part of the client. The client need not worry about the details of creating applications, building/maintaining platforms or over-seeing the details of infrastructure (physical data centers). Clients who purchase SaaS Cloud resources are, for the most part, acquiring turn-key access to standing computer tools just waiting to receive their data and begin processing.

At the platform level, client enterprises are served Platform as a Service (PaaS) resources. Clients purchasing PaaS resources abdicate the responsibility for platform construction/maintenance and the maintenance of infrastructure to the Cloud supplier, but they take upon themselves the task of either building their own custom applications or else installing apps supplied by third parties, and making sure they work well in concert. PaaS support offerings will usually include tools for application design, development, testing, deployment and hosting as well as services such as team collaboration,web service integration,along with database integration, security, scalability, storage, persistence, state management, application versioning, application instrumentation and developer community facilitation.

Lastly, client enterprises accessing the Cloud in an Infrastructure as a Service (IaaS) paradigm take it upon themselves to build/maintain their own platforms and applications. These clients are basically just purchasing raw computing capacity and storage.

Differentiating Public, Private and Hybrid Cloud Environments :

When most people speak of Cloud Computing, they generally mean a “public Cloud.” In a public Cloud a provider such as Amazon or Google makes computing resources (such as processing power, memory or storage) publicly available over the internet. In a public Cloud, the pay-as-you go model is present in its purest form, and resources are shared between all subscribers. Public Clouds typically run on open-source software to facilitate the movement of vast amounts of data. However, an increasing number of software companies (including Microsoft and Oracle) are beginning to provide Cloud infrastructures utilizing proprietary software.

Public Clouds are generally perceived – to an increasing extent, unfairly, as shall be shown in a later chapter – to be insecure environments where an organization’s data is liable to theft, spying or destruction. This perception has helped two other types of computing Clouds rise in popularity: the private Cloud and the hybrid cloud.

The term “private Cloud” refers to privately-held, discrete computing infrastructures that have capabilities similar to a Cloud but are not shared by diverse organizations. Although this paradigm eliminates many of the cost-benefits of Cloud Computing, it still allows for virtualization to simulate resource allocation, and therefore can save on at least some costs while also assuring an impregnable – albeit pricey – operating environment.

Of increasing popularity is the hybrid Cloud, which allows for most of the cost-savings associated with public Clouds, while also offering proprietary security. In a hybrid Cloud, a significant amount of processing and data storage gets transacted on a public Cloud, and the balance in a private Cloud. Most organizations have sensitive and non-sensitive information and applications. Not all data and not all operations need be bullet-proof. In most hybrid Clouds, the database servers containing sensitive proprietary information are kept on a private Cloud, while a public cloud is used for everything else.


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Pubblicato da su agosto 17, 2012 in Computer Clouding