D316 Certmaster 5C and 5D Questions
with Verified Answers
Trivial File Transfer Protocol (TFTP)
-Simplified form of FTP supporting only file copying. TFTP works over UDP port 69.
-This protocol is typically used by network devices to obtain a configuration file. The application
protocol uses its own acknowledgement messaging, so it does not require TCP.
Server port number
are assigned by the Internet Assigned Numbers Authority (IANA)
True or false? At the Transport layer, connections between hosts to exchange
application data are established over a single port number.
False. The server application is identified by one port, but the client must also assign its
own port to track the connection.
Another technician has scribbled some notes about a firewall configuration. The technician
has listed only the port numbers 25 and 3389. What is the purpose of the protocols that
use these ports by default?
Port TCP/25 is used by the Simple Mail Transfer Protocol (SMTP) to send and receive email
messages. Port TCP/3389 is used by Remote Desktop Protocol (RDP) to connect to a
computer's graphical shell over the network.
The technician has made a note to check that port 445 is blocked by the firewall. What is the
purpose of the protocol that uses this port by default, and why should it be blocked?
Port TCP/445 is used by the Server Message Block (SMB) protocol that implements Windows
File/Printer Sharing. SMB is designed for use on local networks only. Allowing access from the
Internet would be a security risk.
What feature of DHCP means that it must use UDP at the transport layer?
, The Dynamic Host Configuration Protocol (DHCP) uses broadcast addressing, which is not
supported by the connection-oriented Transmission Control Protocol (TCP).
Consequently, DHCP uses the connectionless User Datagram Protocol (UDP).
When an interface is assigned a static configuration manually
the installer may make a mistake with the address information—perhaps duplicating an
existing IP address or entering the wrong subnet mask—or the configuration of the network
may change, requiring the host to be manually configured with a new static address. To avoid
these problems, a DHCP server can be used to allocate an appropriate IP address and subnet
mask (plus other settings) to any host that connects to the network and requests address
information.
Scope
Range of consecutive IP addresses in the same subnet that a DHCP server can lease to clients.
DHCP Scope
is the range of addresses that a DHCP server can offer to client hosts in a particular subnet.
The scope should exclude any addresses that have been configured statically. For example, the
LAN address of a SOHO router is typically 192.168.0.1 . This is also the address used by the
DHCP server running on the router. The scope must exclude this address. If the scope is
defined as 192.168.0.100 to 192.168.0.199 , that allows for 100 dynamically addressed hosts
on the local network.
DHCP Leases
-A host is configured to use DHCP by specifying in its TCP/IP configuration that it should
automatically obtain an IP address. When a DHCP client initializes, it broadcasts a
DHCPDISCOVER packet to find a DHCP server. All communications are sent using UDP, with the
server listening on port 67 and the client on port 68.
The DHCP client
with Verified Answers
Trivial File Transfer Protocol (TFTP)
-Simplified form of FTP supporting only file copying. TFTP works over UDP port 69.
-This protocol is typically used by network devices to obtain a configuration file. The application
protocol uses its own acknowledgement messaging, so it does not require TCP.
Server port number
are assigned by the Internet Assigned Numbers Authority (IANA)
True or false? At the Transport layer, connections between hosts to exchange
application data are established over a single port number.
False. The server application is identified by one port, but the client must also assign its
own port to track the connection.
Another technician has scribbled some notes about a firewall configuration. The technician
has listed only the port numbers 25 and 3389. What is the purpose of the protocols that
use these ports by default?
Port TCP/25 is used by the Simple Mail Transfer Protocol (SMTP) to send and receive email
messages. Port TCP/3389 is used by Remote Desktop Protocol (RDP) to connect to a
computer's graphical shell over the network.
The technician has made a note to check that port 445 is blocked by the firewall. What is the
purpose of the protocol that uses this port by default, and why should it be blocked?
Port TCP/445 is used by the Server Message Block (SMB) protocol that implements Windows
File/Printer Sharing. SMB is designed for use on local networks only. Allowing access from the
Internet would be a security risk.
What feature of DHCP means that it must use UDP at the transport layer?
, The Dynamic Host Configuration Protocol (DHCP) uses broadcast addressing, which is not
supported by the connection-oriented Transmission Control Protocol (TCP).
Consequently, DHCP uses the connectionless User Datagram Protocol (UDP).
When an interface is assigned a static configuration manually
the installer may make a mistake with the address information—perhaps duplicating an
existing IP address or entering the wrong subnet mask—or the configuration of the network
may change, requiring the host to be manually configured with a new static address. To avoid
these problems, a DHCP server can be used to allocate an appropriate IP address and subnet
mask (plus other settings) to any host that connects to the network and requests address
information.
Scope
Range of consecutive IP addresses in the same subnet that a DHCP server can lease to clients.
DHCP Scope
is the range of addresses that a DHCP server can offer to client hosts in a particular subnet.
The scope should exclude any addresses that have been configured statically. For example, the
LAN address of a SOHO router is typically 192.168.0.1 . This is also the address used by the
DHCP server running on the router. The scope must exclude this address. If the scope is
defined as 192.168.0.100 to 192.168.0.199 , that allows for 100 dynamically addressed hosts
on the local network.
DHCP Leases
-A host is configured to use DHCP by specifying in its TCP/IP configuration that it should
automatically obtain an IP address. When a DHCP client initializes, it broadcasts a
DHCPDISCOVER packet to find a DHCP server. All communications are sent using UDP, with the
server listening on port 67 and the client on port 68.
The DHCP client
