Module-15

What part of the URL, http://www.cisco.com/index.html, represents the top-level DNS domain?

.com Topic 15.4.0 - The components of the URL http://www.cisco.com/index.html are as follows: http = protocol www = part of the server name cisco = part of the domain name index = file name com = the top-level domain

How many connections are required by FTP between client and server?

2 FTP requires two connections between the client and the server. One connection is over port 21 for client commands and server replies. The other connection is over port 20 for data transfer.

Which of these ports are used by FTP? (Choose two.)

20 21 Ports 20 and 21 are used by FTP.

Which of the following DNS record types is used to resolve IPv6 addresses?

AAAA DNS AAAA records are used to resolve names to IPv6 addresses.

These three OSI layers define the same functions as the TCP/IP model application layer.

Application Presentation Session The upper three OSI layers; application, presentation, and session, define the application layer functions of the TCP/IP model.

Which TCP/IP model layer is closest to the end user?

Application Topic 15.1.0 - End users use applications to interact with and use the network. The application layer of the TCP/IP model is closest to the end user. Application layer protocols are used to communicate and exchange messages with other network devices and applications. The layers of the TCP/IP model are from top to bottom (memory aid - ATIN): application, transport, internet, network access

MODULE-15 END-OF-CHAPTER-QUIZ

Application Layer

MODULE 15

Application, Session, Presentation

Which peer-to-peer application allows users to share pieces of many files with each other at the same time?

BitTorrent BitTorrent clients use a torrent file to locate other clients that are sharing pieces of needed files. In this way, many files can be shared between clients at the same time.

A wireless host needs to request an IPv4 address. What protocol would be used to process the request?

DHCP Topic 15.4.0 - The DHCP protocol is used to request, issue, and manage IP addressing information. CSMA/CD is the access method used with wired Ethernet. ICMP is used to test connectivity. SNMP is used with network management and FTP is used for file transfer.

Which two are protocols that belong in the OSI application layer?

DNS SMTP The application layer of the OSI model provides an interface between applications protocols exchanging data between hosts. Protocols at the application layer include DNS, HTTP, SMTP, FTP, and IMAP.

True or false? HTTP is a secure protocol.

False The correct answer is False. HTTP sends information in plaintext and is not considered secure. If security is desired, HTTP Secure (HTTPS) should be used.

True or false? The peer-to-peer networking model requires the implementation of a dedicated server for data access.

False The correct answer is False. In the peer-to-peer model, clients can share resources without using a dedicated server.

True or false? Resource sharing over SMB is only supported on Microsoft operating systems.

False The correct answer is False. Resource sharing over SMB is also supported by Apple Macintosh. Linux and Unix operating systems use a version of SMB called SAMBA.

True or false? DHCP clients send a DHCP request message to available DHCP servers.

False The correct answer is False. There are four DHCP messages exchanged between clients and servers. The client initiates the DHCP process with a DHCP discover message to available DHCP servers.

True or false? A DNS server that receives a request for a name resolution that is not within its DNS zone will send a failure message to the requesting client.

False The correct answer is False. When a DNS server receives a name resolution request for a name not within its zone, the server will forward the request to another DNS server.

MODULE-15 FILE SHARING SERVICES

File Sharing Services

What message type is used by an HTTP client to request data from a web server?

GET Topic 15.3.0 - HTTP clients send GET messages to request data from web servers.

This protocol is used by a web browser to establish a connection to a web server.

HTTP Web browsers connect to web servers over HTTP. IMAP and SMTP are email protocols. SSL is an encryption protocol used with HTTPS.

Which protocol uses encryption?

HTTPS Topic 15.1.0 - HTTPS uses Secure Socket Layer (SSL) to encrypt traffic accessed from a web server.

When retrieving email messages, which protocol allows for easy, centralized storage and backup of emails that would be desirable for a small- to medium-sized business?

IMAP Topic 15.3.0 - IMAP is preferred for small-to medium-sized businesses as IMAP allows centralized storage and backup of emails, with copies of the emails being forwarded to clients. POP delivers the emails to the clients and deletes them on the email server. SMTP is used to send emails and not to receive them. HTTPS is not used for secure web browsing.

MODULE-15 IP ADDRESSING SERVICES

IP Addressing Services

Which is a feature of IMAP?

It downloads a copy of email messages leaving the original on the server. IMAP is a protocol for clients to retrieve copies of email messages from an IMAP server. The original messages remain on the server until manually deleted.

This message type is used when uploading data files to a web server.

POST HTTP uses the POST message to upload data files to a web server. The GET message is used by clients to request data and the PUT message is used to upload content such as images.

Why is DHCP for IPv4 preferred for use on large networks?

It is a more efficient way to manage IP addresses than static address assignment. Topic 15.4.0 - Static IPv4 address assignment requires personnel to configure each network host with addresses manually. Large networks can change frequently and have many more hosts to configure than do small networks. DHCP provides a much more efficient means of configuring and managing IPv4 addresses on large networks than does static address assignment.

Which three protocols or standards are used at the application layer of the TCP/IP model? (Choose three.)

MPEG HTTP GIF Topic 15.1.0 - HTTP, MPEG, and GIF operate at the application layer of the TCP/IP model. TCP and UDP operate at the transport layer. IP operates at the internet layer.​

MODULE-15 Peer-to-Peer

Peer-to-Peer

Which of the following DNS resource record types resolves authoritative name servers?

NS NS records resolve authoritative name servers. DNS A records resolve IPv4 addresses. AAAA records resolve IPv6 addresses, and MX records resolve mail exchange servers.

Which protocol can be used to transfer messages from an email server to an email client?

POP3 Topic 15.3.0 - SMTP is used to send mail from the client to the server but POP3 is used to download mail from the server to the client. HTTP and SNMP are protocols that are unrelated to email.

Which application layer protocol is used to provide file-sharing and print services to Microsoft applications?

SMB Topic 15.5.0 - SMB is used in Microsoft networking for file-sharing and print services. The Linux operating system provides a method of sharing resources with Microsoft networks by using a version of SMB called SAMBA.

This protocol is used by a client to send email to a mail server.

SMTP Email clients connect to SMTP servers over port 25 to send email. POP and IMAP are used by clients to receive email. HTTP is used between web browsers and web servers.

Which statement is true about FTP?

The client can download data from or upload data to the server. Topic 15.5.0 - FTP is a client/server protocol. FTP requires two connections between the client and the server and uses TCP to provide reliable connections. With FTP, data transfer can happen in either direction. The client can download (pull) data from the server or upload (push) data to the server.

True or false? In a peer-to-peer network environment every peer can function as both a client and a server.

True The correct answer is True. A peer-to-peer network does not require a dedicated server because each peer can function as both a client and as a server.

True or false? FTP data transfers take place from client to server (push) and from server to client (pull).

True The correct answer is True. Data transfer over FTP can take place in either direction, uploads from client to server, or downloads from server to client.

Which of the following is a feature of the Gnutella protocol?

Users can share whole files with other users. Gnutella is a peer-to-peer protocol that allows users to share whole files with other users.

MODULE-15 WEB AND EMAIL PROTOCOLS

Web and Email Protocols

On a home network, which device is most likely to provide dynamic IPv4 addressing to clients on the home network?

a home router Topic 15.4.0 - On a home network, a home router usually serves as the DHCP server. The home router is responsible for dynamically assigning IPv4 addresses to clients on the home network. ISPs also use DHCP, but it usually assigns an IPv4 address to the Internet interface of the home router, not the clients on the home network. In businesses, it is common to have a file or other dedicated server provide DHCP services to the network. Finally, a DNS server is responsible for finding the IP address for a URL, not for providing dynamic addressing to network clients.

This layer of the OSI model is concerned with the protocols that exchange data between programs running on hosts.

application The application layer of the OSI model is the layer that is closest to the end user. It provides an interface between application protocols exchanging data between hosts.

An author is uploading one chapter document from a personal computer to a file server of a book publisher. What role is the personal computer assuming in this network model?

client Topic 15.2.0 - In the client/server network model, a network device assumes the role of server in order to provide a particular service such as file transfer and storage. The device requesting the service assumes the role of client. In the client/server network model, a dedicated server does not have to be used, but if one is present, the network model being used is the client/server model. In contrast, the peer-to-peer network model does not have a dedicated server.

This is a function of the OSI session layer.

exchange of information to imitate dialog between peers The session layer of the OSI model creates and maintains the dialogs, or sessions, between two communicating hosts.

Which two tasks can be performed by a local DNS server? (Choose two.)

mapping name-to-IP addresses for internal hosts forwarding name resolution requests between servers Topic 15.4.0 - Two important functions of DNS are to (1) provide IP addresses for domain names such as www.cisco.com, and (2) forward requests that cannot be resolved to other servers in order to provide domain name to IP address translation. DHCP provides IP addressing information to local devices. A file transfer protocol such as FTP, SFTP, or TFTP provides file sharing services. IMAP or POP can be used to retrieve an email message from a server.

MKV, GIF, and JPG standards are associated with which OSI layer?

presentation The presentation layer is concerned with formatting and presenting data in a format that is compatible with the destination device. Examples of presentation layer standards are MKV, GIF, JPG, MOV, and PNG.

Which of the following is displayed by the nslookup utility?

the configured default DNS server By issuing the nslookup command, the default DNS server that is configured is displayed.

What are two characteristics of the application layer of the TCP/IP model? (Choose two.)

the creation and maintenance of dialogue between source and destination applications closest to the end user Topic 15.1.0 - The application layer of the TCP/IP model is the layer that is closest to the end user, providing the interface between the applications. It is responsible for formatting, compressing, and encrypting data, and is used to create and maintain dialog between source and destination applications.