- Which two definitions accurately describe the associated application layer protocol? (Choose two.)
- SMTP – transfers web pages from web servers to clients
- Telnet – provides remote access to servers and networking devices*
- DNS – resolves Internet names to IP addresses*
- FTP – transfers email messages and attachments
- HTTP – enables devices on a network to obtain IP addresses
Explain:
The Domain Name Service (DNS) protocol resolves Internet names to IP
addresses. Hypertext Transfer Protocol (HTTP) transfers files that make
up the web pages of the World Wide Web. The Simple Mail Transfer
Protocol (SMTP) transfers mail messages and attachments. Telnet, a
terminal emulation protocol, provides remote access to servers and
networking devices. The File Transfer Protocol (FTP) transfers files
between systems.
- The application layer of the TCP/IP model performs the functions of what three layers of the OSI model? (Choose three.)
- physical
- session*
- network
- presentation*
- data link
- transport
- application*
Explain:
The network access layer of the TCP/IP model performs the same functions
as the physical and data link layers of the OSI model. The internetwork
layer equates to the network layer of the OSI model. The transport
layers are the same in both models. The application layer of the TCP/IP
model represents the session, presentation, and application layers of
the OSI model.
- Which layer in the TCP/IP model is used for formatting, compressing, and encrypting data?
- internetwork
- session
- presentation
- application*
- network access
Explain:
The application layer of the TCP/IP model performs the functions of
three layers of the OSI model – application, presentation, and session.
The application layer of the TCP/IP model is the layer that provides the
interface between the applications, is responsible for formatting,
compressing, and encrypting data, and is used to create and maintain
dialogs between source and destination applications.
- What are two characteristics of the application layer of the TCP/IP model? (Choose two.)
- responsibility for logical addressing
- responsibility for physical addressing
- the creation and maintenance of dialogue between source and destination applications *
- closest to the end user*
- the establishing of window size
Explain:
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.
- A manufacturing company subscribes to certain hosted
services from its ISP. The services that are required include hosted
world wide web, file transfer, and e-mail. Which protocols represent
these three key applications? (Choose three.)
- FTP*
- HTTP*
- DNS
- SNMP
- DHCP
- SMTP*
Explain:
The ISP uses the HTTP protocol in conjunction with hosting web pages,
the FTP protocol with file transfers, and SMTP with e-mail. DNS is used
to translate domain names to IP addresses. SNMP is used for network
management traffic. DHCP ic commonly used to manage IP addressing.
- What is an example of network communication that uses the client-server model?
- A user uses eMule to download a file that is shared by a friend after the file location is determined.
- A workstation initiates an ARP to find the MAC address of a receiving host.
- A user prints a document by using a printer that is attached to a workstation of a coworker.
- A workstation initiates a DNS request when the user types www.cisco.com in the address bar of a web browser.*
Explain:
When a user types a domain name of a website into the address bar of a
web browser, a workstation needs to send a DNS request to the DNS server
for the name resolution process. This request is a client/server model
application. The eMule application is P2P. Sharing a printer on a
workstation is a peer-to-peer network. Using ARP is just a broadcast
message sent by a host.
- Two students are working on a network design project. One
student is doing the drawing, while the other student is writing the
proposal. The drawing is finished and the student wants to share the
folder that contains the drawing so that the other student can access
the file and copy it to a USB drive. Which networking model is being
used?
- peer-to-peer*
- client-based
- master-slave
- point-to-point
Explain:
In a peer-to-peer (P2P) networking model, data is exchanged between two
network devices without the use of a dedicated server.
- What do the client/server and peer-to-peer network models have in common?
- Both models have dedicated servers.
- Both models support devices in server and client roles.*
- Both models require the use of TCP/IP-based protocols.
- Both models are used only in the wired network environment.
Explain:
In both the client/server and peer-to-peer network models, clients and
servers exist. In peer-to-peer networks, no dedicated server exists, but
a device can assume the server role to provide information to a device
serving in the client role.
- What is an advantage for small organizations of adopting IMAP instead of POP?
- Messages are kept in the mail servers until they are manually deleted from the email client.*
- When the user connects to a POP server, copies of the messages are
kept in the mail server for a short time, but IMAP keeps them for a long
time.
- IMAP sends and retrieves email, but POP only retrieves email.
- POP only allows the client to store messages in a centralized way, while IMAP allows distributed storage.
Explain:
IMAP and POP are protocols that are used to retrieve email messages. The
advantage of using IMAP instead of POP is that when the user connects
to an IMAP-capable server, copies of the messages are downloaded to the
client application. IMAP then stores the email messages on the server
until the user manually deletes those messages.
- Which application layer protocol uses message types such as GET, PUT, and POST?
Explain:
The GET command is a client request for data from a web server. A PUT
command uploads resources and content, such as images, to a web server. A
POST command uploads data files to 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?
Explain:
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.
- Which three statements describe a DHCP Discover message? (Choose three.)
- The source MAC address is 48 ones (FF-FF-FF-FF-FF-FF).
- The destination IP address is 255.255.255.255.*
- The message comes from a server offering an IP address.
- The message comes from a client seeking an IP address.*
- All hosts receive the message, but only a DHCP server replies.*
- Only the DHCP server receives the message.
Explain:
When a host configured to use DHCP powers up on a network it sends a
DHCPDISCOVER message. FF-FF-FF-FF-FF-FF is the L2 broadcast address. A
DHCP server replies with a unicast DHCPOFFER message back to the host.
- What part of the URL, http://www.cisco.com/index.html, represents the top-level DNS domain?
Explain:
The components of the URL http://www.cisco.com/index.htm 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
- Which two tasks can be performed by a local DNS server? (Choose two.)
- providing IP addresses to local hosts
- allowing data transfer between two network devices
- mapping name-to-IP addresses for internal hosts*
- forwarding name resolution requests between servers*
- retrieving email messages
Explain:
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.
- Which phrase describes an FTP daemon?
- a diagnostic FTP program
- a program that is running on an FTP server*
- a program that is running on an FTP client
- an application that is used to request data from an FTP server
Explain:
An FTP server runs an FTP daemon, which is a program that provides FTP
services. End users who request services must run an FTP client program.
- Which statement is true about FTP?
- The client can choose if FTP is going to establish one or two connections with the server.
- The client can download data from or upload data to the server.*
- FTP is a peer-to-peer application.
- FTP does not provide reliability during data transmission.
Explain:
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.
- What is true about the Server Message Block protocol?
- Different SMB message types have a different format.
- Clients establish a long term connection to servers.*
- SMB messages cannot authenticate a session.
- SMB uses the FTP protocol for communication.
Explain:
The Server Message Block protocol is a protocol for file, printer, and
directory sharing. Clients establish a long term connection to servers
and when the connection is active, the resources can be accessed. Every
SMB message has the same format. The use of SMB differs from FTP mainly
in the length of the sessions. SMB messages can authenticate sessions.
- Which application layer protocol is used to provide file-sharing and print services to Microsoft applications?
Explain:
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.
- Fill in the blank.
What is the acronym for the protocol that is used when securely communicating with a web server? HTTPS
Explain:
Hypertext Transfer Protocol Secure (HTTPS) is the protocol that is used
for accessing or posting web server information using a secure
communication channel.
- Fill in the blank.
The HTTP message type used by the client to request data from the web server is the GET message.
Explain:
GET is one of the message types used by HTTP. A client (web browser)
sends the GET message to the web server to request HTML pages.
- Open the PT Activity.
Perform the tasks in the activity instructions and then answer the question.
Which PC or PCs are sending FTP packets to the server?
PC_3
PC_1
PC_2*
PC_1 and PC_3
Explain:
After you view the details of the packets that are being transferred
between each PC and the server, you will see that the PC that is using a
destination port number of 20 or 21 is the PC using the FTP service.
PC_2 has an outbound port number of 21 to create an FTP control session
with the server at 192.168.1.253.
- Fill in the blank.
Refer to the exhibit. What command was used to resolve a given host name by querying the name servers? “ nslookup ”
A user can manually query the name servers to resolve
a given host name using the nslookup command.
Nslookup is both a command and a utility.
Explain:
A user can manually query the name servers to resolve a given host name
using the nslookup command. Nslookup is both a command and a utility.
- Match a statement to the related network model. (Not all options are used.)
Place the options in the following order:
peer-to-peer network
[+] no dedicated server is required
[+] client and server roles are set on a per request basis
peer-to-peer aplication
[#] requires a specific user interface
[#] a background service is required
Explain:
Peer-to-peer networks do not require the use of a dedicated server, and
devices can assume both client and server roles simultaneously on a per
request basis. Because they do not require formalized accounts or
permissions, they are best used in limited situations. Peer-to-peer
applications require a user interface and background service to be
running, and can be used in more diverse situations.
- Match the function to the name of the application. (Not all options are used.)
Place the options in the following order:
— not scored —
DHCP -> dynamically assigns IP address to clients
DNS -> maps URLs to numerical addresses
IMAP -> allows viewing of messages on email clients
HTTP -> displays web pages
SMTP -> sends email messages
— not scored —
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