Network+ Ch 6 Questions

You need to have secure communications using HTTPS. What port number is used by default?

443

What layer 4 protocol is used for a Telnet connection, and what is the default port number?

TCP, 23 Telnet uses TCP at the Transport layer with a default port number of 23.

Which destination Transport-layer protocol and port number does a TFTP client use to transfer files over the network?

TFTP servers respond to UDP messages sent to port 69.

Which UNIX command is used for terminal emulation in the same way Telnet is used?

The UNIX command rlogin functions similarly to Telnet.

What might be the problem if a DHCP client suddenly finds itself in a different IP subnet from the one it should be in?

The most likely problem is that a rogue DHCP server has been introduced into the network and is handing this device an incorrect lease.

If you can ping by IP address but not by hostname, or FQDN, which of the following port numbers is related to the server process that is involved?

The problem is with DNS, which uses both TCP and UDP port 53.

If you use either Telnet or FTP, which is the highest layer you are using to transmit data?

. Application, Both FTP and Telnet use TCP at the Transport layer; however, they both are Application layer protocols, so the Application layer is the best answer for this question.

What two well-known port numbers does a DNS server use?

A DNS server uses TCP port 53 for zone transfers and UDP port 53 for name resolutions.

Which of the following services use UDP? (Choose three.)

A, C, F. DHCP, SNMP, and TFTP use UDP. SMTP, FTP, and HTTP use TCP.

Which of the following describe the DHCP Discover message? (Choose two.)

A. It uses FF:FF:FF:FF:FF:FF as a Layer 2 broadcast. B. It uses UDP as the Transport layer protocol. A client that sends out a DHCP Discover message in order to receive an IP address sends out a broadcast at both Layer 2 and Layer 3. The Layer 2 broadcast is all Fs in hex, or FF:FF:FF:FF:FF:FF. The Layer 3 broadcast is 255.255.255.255, which means all networks and all hosts. DHCP is connectionless, which means it uses User Datagram Protocol (UDP) at the Transport layer, also called the Host-to-Host layer.

Which of the following allows a server to distinguish among different simultaneous requests from the same host?

A. They have different port numbers. Through the use of port numbers, TCP and UDP can establish multiple sessions between the same two hosts without creating any confusion. The sessions can be between the same or different applications, such as multiple web-browsing sessions or a web-browsing session and an FTP session.

What protocol is used to find the hardware address of a local device?

Address Resolution Protocol (ARP) is used to find the hardware address from a known IP address.

The OSI has seven layers, which layer does SMTP work at?

Application

You need to transfer files between two hosts. Which two protocol can you use?

B, E. Secure Copy Protocol (SCP), and File Transfer Protocol (FTP), can be used to transfer files between two systems.

What layer in the IP stack is equivalent to the Transport layer of the OSI model?

B. Host-to-Host, The four layers of the IP stack (also called the DoD model) are Application/Process, Host-to-Host, Internet, and Network Access. The Host-to-Host layer is equivalent to the Transport layer of the OSI model.

Which of the following protocols can use TCP and UDP, permits authentication and secure polling of network devices, and allows for automated alerts and reports on network devices?

B. SNMP Simple Network Management Protocol, is typically implemented using version 3, which allows for a connection oriented service, authentication and secure polling of network devices, and allows for alerts and reports on network devices.

Which of the following are TCP/IP protocols used at the Application layer of the OSI model? (Choose three.)

C, D, E. Telnet, File Transfer Protocol (FTP), and Trivial FTP (TFTP) are all Application layer protocols. IP is a Network layer protocol. Transmission Control Protocol (TCP) is a Transport layer protocol.

You need to make sure that your network devices have a consistent time across all devices. What protocol do you need to run on your network?

C. NTP Network Time Protocol will ensure a consistent time across network devices on the network.

Which of the following protocols is used by e-mail servers to exchange messages with one another?

C. SMTP is used by a client to send mail to its server and by that server to send mail to another server. POP3 and IMAP are used by clients to retrieve their mail from the server that stores it until it is retrieved. HTTP is only used with web-based mail services.

Which statements are true regarding ICMP packets? (Choose two.)

C. They can provide hosts with information about network problems. D. They are encapsulated within IP datagrams. E. They are encapsulated within UDP datagrams. C, D. Internet Control Message Protocol (ICMP) is used to send error messages through the network, but ICMP does not work alone. Every segment or ICMP payload must be encapsulated within an IP datagram (or packet).

Which of the following protocols uses both TCP and UDP?

D. DNS uses TCP for zone exchanges between servers and UDP when a client is trying to resolve a hostname to an IP address.

You want to implement a mechanism that automates the IP configuration, including IP address, subnet mask, default gateway, and DNS information. Which protocol will you use to accomplish this?

DHCP Dynamic Host Configuration Protocol (DHCP) is used to provide IP information to hosts on your network. DHCP can provide a lot of information, but the most common is IP address, subnet mask, default gateway, and DNS information.

Which of the following services use TCP? (Choose three.)

E. SMTP, FTP, and HTTP use TCP.

Name the protocol that uses both TCP ports 20 and 21.

FTP uses both TCP ports 20 and 21 for the data channel and the control channel, respectively.

What protocol is at the heart of the ping and tracert commands in a Windows operating system?

ICMP is the protocol that the ping and tracert commands rely on. If you're having trouble getting pings and Traceroutes through a router, you might need to check if ICMP is being allowed thorough.

Which protocol dynamically reports errors to source hosts by using IP directly to build packets?

ICMP uses IP directly to build error-reporting packets that are transmitted back to the originating source host when issues arise during the delivery of data packets. ICMP is also used during ping and some Traceroute operations.

What might cause your email to stop functioning properly when you change Internet service providers?

Most ISPs have their own mail servers. When you switch service, you might need to point your mail application to the servers provided by the new service provider.

What could cause a server that you can ping not to provide the particular TCP/IP service, such as FTP, HTTP, and so on, that you expect it to offer?

Quite simply, the service might not be running currently on that server. Another possibility might be that a firewall between the client and the server has blocked the protocol in question from passing.

What well-known port numbers do SMTP, POP3, and IMAP4 servers use?

SMTP uses TCP port 25; POP3 uses TCP port 110; IMAP4 uses TCP port 143.

You need to login to a Unix server across a network that is not secure. Which of the following protocols will allow you to remotely administrator this server securely?

Secure Shell (SSH) allows you to remotely administer router, switches and even servers securely.