Network+ Questions

Started by certforumz, July 12, 2011, 09:03:49 PM

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certforumz

Which of the following is an advantage of using virtual machines over physical computers for malware behavior analysis?


A) OS licensing for virtual machines is free if the hosting OS matches the guest OS

B) Virtual environments provide the ability to easily roll back to previous configurations

C) Working in a virtual environment is faster than on physical computers

D) Some malware may not exhibit malicious behavior in a virtual environment

ans: B

Virtual environments provide the ability to easily roll back to previous configurations

certforumz

Which of the following is the least fault tolerant of all networking topologies?

a. Ring
b. Bus
c. Star
d. Mesh

ans. b

Explanation:

Bus Topology
Bus networks (not to be confused with the system bus of a computer) use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

Ethernet bus topologies are relatively easy to install and don't require much cabling compared to the alternatives. 10Base-2 ("ThinNet") and 10Base-5 ("ThickNet") both were popular Ethernet cabling options many years ago for bus topologies. However, bus networks work best with a limited number of devices. If more than a few dozen computers are added to a network bus, performance problems will likely result. In addition, if the backbone cable fails, the entire network effectively becomes unusable.

Ring Topology:

In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise"). A failure in any cable or device breaks the loop and can take down the entire network. To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. Ring topologies are found in some office buildings or school campuses.

Star Topology:

Many home networks use the star topology. A star network features a central connection point called a "hub node" that may be a network hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet.

Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computer's network access and not the entire LAN. (If the hub fails, however, the entire network also fails.)

Tree Topology:


Tree topologies integrate multiple star topologies together onto a bus. In its simplest form, only hub devices connect directly to the tree bus, and each hub functions as the root of a tree of devices. This bus/star hybrid approach supports future expandability of the network much better than a bus (limited in the number of devices due to the broadcast traffic it generates) or a star (limited by the number of hub connection points) alone.

Mesh Topology:

Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination. (Recall that even in a ring, although two cable paths exist, messages can only travel in one direction.) Some WANs, most notably the Internet, employ mesh routing.

A mesh network in which every device connects to every other is called a full mesh. As shown in the illustration below, partial mesh networks also exist in which some devices connect only indirectly to others.



Vijayb

Q1. Which of the following is Class C IP address? 

                A.      10.10.14.118

                B.      135.23.112.57

                C.      191.200.199.199

                D.      204.67.118.54

Correct Answer: D.

Explanation: IP addresses are written using decimal numbers separated by decimal points. This is called dotted decimal notation of expressing IP addresses.

The different classes of IP addresses is as below:

Class    Format       Leading Bits     Network address Range   Max. # of networks 
A         N.H.H.H                   0                        0 - 126                                         127   

B         N.N.H.H                 10                   128 - 191                                      16,384     

C         N.N.N.H               110                   192 - 223                                  2,097,152                 

Network address of all zeros means "This network or segment".

Network address of all 1s means " all networks", same as hexadecimal of all Fs.

Network number 127 is reserved for loopback tests.

Host(Node)  address of all zeros mean "This Host (Node)".
Host (Node) address of all 1s mean "all Hosts (Nodes) " on the specified network.

Vijayb

#3
Q2. Please see the Diagram, and identify which LAN technology is being used?




                     A.      Ethernet

                    B.      Token Ring

                    C.      Mesh

                    D.      ATM

Correct Answer: B.

Explanation: Ring In and Ring Out connectors are used in Token Ring, for connecting to other MSAUs (Multi-Station Access Units). The cable connecting Ring In and Ring Out is called "Patch cable".

Vijayb

Q3. A Windows 95 user complains that she cannot connect to any other computers on her local subnet even when using the IP address to communicate. However, she can ping 127.0.0.1 and receive a reply. Other users on her subnet do not report having any trouble. All client computers on the network are WINS-enabled. What is the most probable cause of the problem?

         A.      The TCP/IP stack is not installed properly

         B.      The subnet mask is not correct, check whether the subnet mask is configured correctly.

         C.      The default gateway is not configured properly.

         D.      The computer is not configured to use LMHOSTS

Correct Answer: B.

Explanation:

The most likely cause is that the subnet mask is not configured properly. If the TCP/IP stack is not installed properly, you will not be able to ping the local host (127.0.0.1). Also, even if the default gateway is wrongly configured, you will at least be able to ping the computers on the local subnet.

Vijayb

Q4. You have set up a server that connects to an Internet services provider ( ISP) over ISDN line. How should the default gateway address be configured so that windows 95 users on the local network can access the Internet through the RAS server. The RAS server is located on the same subnet as that of the WIN95 machines.

    A. The default Gateway address on WINS95 must specify the IP address of the remote ISP

    B. The default Gateway on WN95 must specify the IP address of the RAS server on the local network.
    C. The HOSTS file in WIN95 machines must be configured with the host name of the RAS Server.

    D. The HOSTS file in WIN 95 machines must be configured with the host name of the ISP

Correct Answer: B.

Explanation:

The default Gateway address on WIN95 machines must specify the IP address of the RAS server.

Vijayb

Q5. Which of the following is the standard adopted for Ethernet CSMA/CD by IEEE Committee?

          A.      802.2
          B.      802.1d
          C.      802.3
          D.      802.5

Correct Answer: C.

Explanation: The IEEE protocols that map to the physical layer are:

Ethernet: IEEE 802.3

Token Passing Bus: 802.4

TokenRing: 802.5

Vijayb

Q6.     Disk Striping with Parity corresponds to which RAID level?

                 A.      RAID 0
                 B.      RAID 1
                 C.      RAID 3
                 D.      RAID 5

Correct Answer: D.

Explanation: RAID stands for Redundant Array of Inexpensive Disks.

Most widely used RAID levels are:

RAID 0: Disk Striping

RAID 1: Disk Mirroring

RAID 5: Disk Striping with Parity

WIndows NT supports RAID levels 0,1, and 5.

Vijayb

Q7. Which of the following media types is most susceptible to EMI?

            A.      Fiber Optic
            B.      STP
            C.      Co-axial
            D.      UTP

Correct Answer: D.

Explanation:

UTP stands for Un-shielded Twisted Pair cabling. STP for Shielded Twisted Pair cabling. UTP cabling is most susceptible for EMI. Fiber Optic is least susceptible.

Vijayb

Q8. Which type of connector does a 10BaseT Ethernet cable use?

                A. BNC
                B. RJ-45
                C. RJ-11
                D. MSAU

Correct Answer: B.

Explanation:

10BaseT Ethernet uses RJ-45 connectors at the ends of the UTP cable.

10Base2 Ethernet uses BNC connectors at the ends of the Thinnet (Coax) cable.

Vijayb

Q9. Which of the following is suitable for mission critical and time sensitive applications?

                 A.      10BaseT
                 B.      10Base2
                 C.      Token Ring
                 D.      Mesh

Correct Answer: C.

Explanation:

Token Ring is most suitable for mission critical applications as it would guarantee the time slot for every work station on the ring. If required, the station priorities can be set.

Vijayb

Q10. What is the default subnet mask for Class C network?

     A.      255.0.0.0
     B.      255.255.0.0
     C.      255.255.255.0
     D.      255.0.255.0

Correct Answer: C.

Explanation:

The default subnet mask for

Class A network: 255.0.0.0

Class B network: 255.255.0.0

Class C network: 255.255.255.0

Vijayb

Q1. You are Telnetting to a remote host on the Internet. Which protocol is being used?

    A.     UDP
    B.     TCP
    C.     HTTP
    D.     FTP
Answer / Explanation: B

The Telnet program is an OSI Application Layer protocol that runs on your computer and connects your PC (a client) to a server on the network. You can then enter commands through the Telnet program and they will be executed as if you were entering them directly on the server console. This enables you to configure and control the server resources remotely.

Other application layer (Layer 7 of OSI) protocols include Network Time Protocol (NTP),Simple Network Management Protocol (SNMP), and File Transfer Protocol (FTP).

Note that the application layer protocols may use TCP or UDP for communication with peers. For example,FTP and Telnet use TCP where as Trivial File Transfer Protocol (TFTP) uses UDP.

HTTP is also an example of Application layer protocol that uses TCP for communicating.

Vijayb

Q2.Which of the following is a Class B network address?

    A.   19.155.26.22
    B.   127.0.0.1
    C.   128.23.44.22
    D.   196.202.202.35
Answer / Explanation: C

IP addresses are written using decimal numbers separated by decimal points. This is called dotted decimal notation of expressing IP addresses. The different classes of IP addresses as per IP v4 specification is as below:

Class    Format       Leading Bits       Network address       Max.nets         Max hosts
A          N.H.H.H           0                        0 - 126                      127             16,777,214
B          N.N.H.H          10                     128 - 191                   16,384              65,534
C          N.N.N.H          110                  192 - 223                 2,097,152              254
D      Not Applicable    1110      Address range:  224.0.0.0 to 239.255.255.255   (Class D multicast address space is 2^28  or 268,435,456 multicast groups.)
E     Not Applicable    1111       Address range: 240.0.0.0     255.255.255.255

Network address of all zeros means  'This network or segment'.
Network address of all 1s means 'all networks', same as hexadecimal of all Fs.
Network number 127 is reserved for loop back tests.
Host (Node) address of all zeros mean 'This Host (Node)'.
Host (Node) address of all 1s mean 'all Hosts (Nodes)' on the specified network.
Class D is a special multicast address and cannot be used for networks. The 4 high-order bits are always 1110, and the remaining 28 bits allow for more than 268 million possible addresses. There is no concept of network and host address ranges in Class D. Class E is reserved for experimental purposes. The first four bits in the address are always 1111.

Vijayb

Q3.What is the directed broadcast address for an IP network 196.233.24.15 with default subnet mask?

     A.   196.233.255.255
     B.   196.255.255.255
     C.   196.0.0.0
     D.   196.233.24.255
Answer / Explanation: D

196.233.24.255/ This is a Class C network with default subnet mask, which is 255.255.255.0. The directed broadcast should reach all Hosts on the intended network (or subnet, if subnetted). Therefore, by putting all 1s for the host potion of the IP address, we get 196.233.24.255.