QUESTION: 5

Which of the following devices is used to convert digital signals to analog signals for transmission across a network?

Gateway
Brouter
Firewall
Modem

Answer(s): D

Explanation:

Modem stands for Modulator-Demodulator. It is a device that enables a computer to transmit information over standard telephone lines. Since a computer stores information digitally and a telephone line is analog, a modem converts digital signals to analog and vice-versa. The conversion of a digital signal to an analog signal is known as modulation and that of an analog signal to a digital signal is known as demodulation.
Answer option A is incorrect.
A gateway is a network point that acts as an entrance to another network. On the Internet, a node or stopping point can be either a gateway node or a host (end-point) node. Both the computers of Internet users and the computers that serve pages to users are host nodes. The computers that control traffic within a company's network or at a local Internet service provider (ISP) are gateway nodes.In the network for an enterprise, a computer server acting as a gateway node is often also acting as a proxy server and a firewall server.
A gateway is often associated with both a router, which knows where to direct a given packet of data that arrives at the gateway, and a switch, which furnishes the actual path in and out of the gateway for a given packet.
Answer option B is incorrect.
A brouter is a network bridge and a router combined in a single product.
A bridge is a device that connects one local area network (LAN) to another local area network that uses the same protocol (for example, Ethernet or Token Ring). If a data unit on one LAN is intended for a destination on an interconnected LAN, the bridge forwards the data unit to that LAN; otherwise, it passes it along on the same LAN.
A bridge usually offers only one path to a given interconnected LAN.
A router connects a network to one or more other networks that are usually part of a wide area network (WAN) and may offer a number of paths out to destinations on those networks.
A router therefore needs to have more information than a bridge about the interconnected networks. It consults a routing table for this information. Since a given outgoing data unit or packet from a computer may be intended for an address on the local network, on an interconnected LAN, or the wide area network, it makes sense to have a single unit that examines all data units and forwards them appropriately.
Answer option C is incorrect.
A firewall is a tool to provide security to a network. It is used to protect an internal network or intranet against unauthorized access from the Internet or other outside networks. It restricts inbound and outbound access and can analyze all traffic between an internal network and the Internet. Users can configure a firewall to pass or block packets from specific IP addresses and ports. An administrator can configure the following settings for a firewall:
Open and Closed Ports: Through this setting firewall determines which data packet to be allowed or drop during communication.

Program Filters: Through program filters, firewall determines which program to be allowed or disallow for communication.
A firewall can be a standalone system, a software application, or a hardware device that blocks/permits traffic. It can also be used to secure the network from malicious activities.

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QUESTION: 6

John works as a Sales Manager for BlueWells Inc. The company has a Windows-based network. John often travels away from the office. He wants to connect his Laptop to the office's local network.
Which of the following mechanisms will he use to connect to the office's local network?

Virtual Private Network (VPN)
Personal Area Network (PAN)
Intranet
Extranet

Answer(s): A

Explanation:

A virtual private network (VPN) is a form of wide area network (WAN) that supplies network connectivity over a possibly long physical distance.
A virtual private network is a network that uses a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization's network.
A virtual private network can be contrasted with an expensive system of owned or leased lines that can only be used by one organization. The goal of a VPN is to provide the organization with the same capabilities, but at a much lower cost.A VPN works by using the shared public infrastructure while maintaining privacy through security procedures and tunneling protocols such as the Layer Two Tunneling Protocol (L2TP). In effect, the protocols, by encrypting data at the sending end and decrypting it at the receiving end, send the data through a tunnel that cannot be entered by data that is not properly encrypted. An additional level of security involves encrypting not only the data, but also the originating and receiving network addresses.
Answer option C is incorrect. An intranet is a private network that is contained within an enterprise. Intranet is used to share company information and computing resources among employees. It is also used to facilitate working in groups and for teleconferencing. An intranet uses TCP/IP, HTTP, and other Internet protocols.
Answer option D is incorrect. Extranet is an area of a Web site, which is available only to selected customers, suppliers, and mobile workers. It allows users limited access to a company's intranet. Extranet can also be considered as an extension of a corporate intranet using the World Wide Web technology to facilitate communication with a corporation's suppliers and customers.
Answer option B is incorrect.
A personal area network (PAN) is a computer network used for communication among computer devices (including telephones and personal digital assistants) close to one's person. The reach of a PAN is typically a few meters.
A PAN can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet.

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QUESTION: 7

Which of the following techniques allows multiple computers to share one or more IP addresses?

NAT
WINS
DHCP
DNS

Answer(s): A

Explanation:

Network address translation (NAT) is a technique that allows multiple computers to share one or more IP addresses. It is configured at a server between a private network and the Internet. It allows the computers in the private network to share a global, ISP assigned address. It modifies the headers of packets traversing the server. For the packets outbound to the Internet, it translates the source addresses from private to public, whereas for the packets inbound from the Internet, it translates the destination addresses from public to private.
Answer option D is incorrect. Domain Name System (DNS) is a hierarchical naming system for computers, services, and resources connected to the Internet or a private network. It is used to translate domain names meaningful to humans into the numerical (binary) identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide. In other words, the Domain Name System is a system that serves as the "phone book" for the Internet by translating human-friendly computer hostnames into IP addresses.
Answer option C is incorrect. DHCP stands for Dynamic Host Configuration Protocol. It is a computer networking protocol that lets network administrators centrally manage and automate the assignment of Internet Protocol (IP) addresses in an organization's network. Using the Internet Protocol, each machine that can connect to the Internet needs a unique IP address, which is assigned when an Internet connection is created for a specific computer. Without DHCP, the IP address must be entered manually at each computer in an organization and a new IP address must be entered each time a computer moves to a new location on the network. DHCP lets a network administrator supervise and distribute IP addresses from a central point and automatically sends a new IP address when a computer is plugged into a different place in the network.DHCP uses the concept of a 'lease' or amount of time that a given IP address will be valid for a computer. The lease time can vary depending on how long a user is likely to require the Internet connection at a particular location. It is especially useful in education and other environments where users change frequently. Using very short leases, DHCP can dynamically reconfigure networks in which there are more computers than there are available IP addresses. The protocol also supports static addresses for computers that need a permanent IP address, such as Web servers.
Answer option B is incorrect. WINS stands for Windows Internet Naming Service. It is a part of the Microsoft Windows NT and 2000 Servers and it is used to manage the association of workstation names and locations with Internet Protocol addresses (IP addresses) without the user or an administrator having to be involved in each configuration change. WINS automatically creates a computer name-IP address mapping entry in a table, ensuring that the name is unique and not a duplicate of someone else's computer name.
When a computer is moved to another geographic location, the subnet part of the IP address is likely to change. Using WINS, the new subnet information will be updated automatically

in the WINS table. WINS complements the NT Server's Dynamic Host Configuration Protocol (DHCP), which negotiates an IP address for any computer (such as workstation) when it is first defined to the network. If a computer user on a network is connected to a Windows NT/2000 server, he may find WINS mentioned in some of the network-related programs or system messages.

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QUESTION: 8

Which Web browser comes with the Windows operating system? Each correct answer represents a complete solution. Choose all that apply.

Internet Explorer
Firefox
Opera
Safari
Lynx

Answer(s): A

Explanation:

Internet Explorer is the Web browser that comes with the Windows operating system.
Answer options E, B, D, and C are incorrect. Lynx, Firefox, Safari, and Opera do not have the Windows operating system.

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