CCNA 2 v7 Modules 7 – 9 Available and Reliable Networks Exam
Answers Cisco Certificate Network Associate
1. A DHCP-enabled client PC has just booted. During which two steps will the client
PC use broadcast messages when communicating with a DHCP server? (Choose two.)
DHCPDISCOVER
DHCPACK
DHCPOFFER
DHCPREQUEST
DHCPNAK
2. An administrator issues the commands:
Router(config)# interface g0/1
Router(config-if)# ip address dhcp
What is the administrator trying to achieve?
configuring the router to act as a DHCPv4 server
configuring the router to obtain IP parameters from a DHCPv4 server
configuring the router to act as a relay agent
configuring the router to resolve IP address conflicts
3. When a client is requesting an initial address lease from a DHCP server, why is the DHCPREQUEST
message sent as a broadcast?
The client does not yet know the IP address of the DHCP server that sent the offer.
The DHCP server may be on a different subnet, so the request must be sent as a
broadcast.
The client does not have a MAC address assigned yet, so it cannot send a unicast
message at Layer 2.
The client may have received offers from multiple servers, and the broadcast serves to
implicitly decline those other offers.
4. Which DHCP IPv4 message contains the following information?
Destination address: 255.255.255.255
,Client IPv4 address: 0.0.0.0
Default gateway address: 0.0.0.0
Subnet mask: 0.0.0.0
DHCPACK
DHCPDISCOVER
DHCPOFFER
DHCPREQUEST
5. Place the options in the following order:
a client initiating a message to find a DHCP server – DHCPDISCOVER
a DHCP server responding to the initial request by a client – DHCPOFFER
the client accepting the IP address provided by the DHCP server – DHCPREQUEST
the DHCP server confirming that the lease has been accepted – DHCPACK 6. Which
protocol automates assignment of IP addresses on a network, and which port number does it use?
(Choose two.)
DHCP
DNS
SMB
53
67
80
Explanation: DNS uses port 53 and translates URLs to IP addresses. SMB provides shared
access to files and printers and uses port 445. Port 80 is used by HTTP. HTTP is a protocol
used to communicate between a web browser and a server.
7. Refer to the exhibit. PC1 is configured to obtain a dynamic IP address from the DHCP server.
PC1 has been shut down for two weeks. When PC1 boots and tries to request an available IP address,
which destination IP address will PC1 place in the IP header?
, 192.168.1.1
192.168.1.255
255.255.255.255
192.168.1.8
Explanation: When a host boots and has been configured for dynamic IP addressing, the device
tries to obtain a valid IP address. It sends a DHCPDISCOVER message. This is a broadcast
message because the DHCP server address is unknown (by design). The destination IP
address in the IP header is 255.255.255.255 and the destination MAC address is
FF:FF:FF:FF:FF:FF.
8. Which message does an IPv4 host use to reply when it receives a DHCPOFFER message from a
DHCP server?
DHCPOFFER
DHCPDISCOVER
DHCPREQUEST
DHCPACK
Explanation: When the client receives the DHCPOFFER from the server, it sends back a
DHCPREQUEST broadcast message. On receiving the DHCPREQUEST message, the server
replies with a unicast DHCPACK message.
, 9. Which command, when issued in the interface configuration mode of a router, enables the
interface to acquire an IPv4 address automatically from an ISP, when that link to the ISP is enabled?
service dhcp
ip address dhcp
ip helper-address
ip dhcp pool
Explanation: The ip address dhcp interface configuration command configures an Ethernet
interface as a DHCP client. The service dhcp global configuration command enables the
DHCPv4 server process on the router. The ip helper-address command is issued to enable
DHCP relay on the router. The ip dhcp pool command creates the name of a pool of addresses
that the server can assign to hosts.
10. Which kind of message is sent by a DHCP client when its IP address lease has expired?
a DHCPDISCOVER unicast message
a DHCPREQUEST broadcast message
a DHCPREQUEST unicast message
a DHCPDISCOVER broadcast message
Explanation: When the IP address lease time of the DHCP client expires, it sends a
DHCPREQUEST unicast message directly to the DHCPv4 server that originally offered the IPv4
address.
11. A host PC is attempting to lease an address through DHCP. What message is sent by the server
to let the client know it is able to use the provided IP information?
DHCPDISCOVER
DHCPOFFER
DHCPREQUEST DHCPACK
DHCPNACK
Explanation: When a host uses DHCP to automatically configure an IP address, the typically
sends two messages: the DHCPDISCOVER message and the DHCPREQUEST message.
These two messages are usually sent as broadcasts to ensure that all DHCP servers receive
them. The servers respond to these messages using DHCPOFFER, DHCPACK, and
DHCPNACK messages, depending on the circumstance.
Answers Cisco Certificate Network Associate
1. A DHCP-enabled client PC has just booted. During which two steps will the client
PC use broadcast messages when communicating with a DHCP server? (Choose two.)
DHCPDISCOVER
DHCPACK
DHCPOFFER
DHCPREQUEST
DHCPNAK
2. An administrator issues the commands:
Router(config)# interface g0/1
Router(config-if)# ip address dhcp
What is the administrator trying to achieve?
configuring the router to act as a DHCPv4 server
configuring the router to obtain IP parameters from a DHCPv4 server
configuring the router to act as a relay agent
configuring the router to resolve IP address conflicts
3. When a client is requesting an initial address lease from a DHCP server, why is the DHCPREQUEST
message sent as a broadcast?
The client does not yet know the IP address of the DHCP server that sent the offer.
The DHCP server may be on a different subnet, so the request must be sent as a
broadcast.
The client does not have a MAC address assigned yet, so it cannot send a unicast
message at Layer 2.
The client may have received offers from multiple servers, and the broadcast serves to
implicitly decline those other offers.
4. Which DHCP IPv4 message contains the following information?
Destination address: 255.255.255.255
,Client IPv4 address: 0.0.0.0
Default gateway address: 0.0.0.0
Subnet mask: 0.0.0.0
DHCPACK
DHCPDISCOVER
DHCPOFFER
DHCPREQUEST
5. Place the options in the following order:
a client initiating a message to find a DHCP server – DHCPDISCOVER
a DHCP server responding to the initial request by a client – DHCPOFFER
the client accepting the IP address provided by the DHCP server – DHCPREQUEST
the DHCP server confirming that the lease has been accepted – DHCPACK 6. Which
protocol automates assignment of IP addresses on a network, and which port number does it use?
(Choose two.)
DHCP
DNS
SMB
53
67
80
Explanation: DNS uses port 53 and translates URLs to IP addresses. SMB provides shared
access to files and printers and uses port 445. Port 80 is used by HTTP. HTTP is a protocol
used to communicate between a web browser and a server.
7. Refer to the exhibit. PC1 is configured to obtain a dynamic IP address from the DHCP server.
PC1 has been shut down for two weeks. When PC1 boots and tries to request an available IP address,
which destination IP address will PC1 place in the IP header?
, 192.168.1.1
192.168.1.255
255.255.255.255
192.168.1.8
Explanation: When a host boots and has been configured for dynamic IP addressing, the device
tries to obtain a valid IP address. It sends a DHCPDISCOVER message. This is a broadcast
message because the DHCP server address is unknown (by design). The destination IP
address in the IP header is 255.255.255.255 and the destination MAC address is
FF:FF:FF:FF:FF:FF.
8. Which message does an IPv4 host use to reply when it receives a DHCPOFFER message from a
DHCP server?
DHCPOFFER
DHCPDISCOVER
DHCPREQUEST
DHCPACK
Explanation: When the client receives the DHCPOFFER from the server, it sends back a
DHCPREQUEST broadcast message. On receiving the DHCPREQUEST message, the server
replies with a unicast DHCPACK message.
, 9. Which command, when issued in the interface configuration mode of a router, enables the
interface to acquire an IPv4 address automatically from an ISP, when that link to the ISP is enabled?
service dhcp
ip address dhcp
ip helper-address
ip dhcp pool
Explanation: The ip address dhcp interface configuration command configures an Ethernet
interface as a DHCP client. The service dhcp global configuration command enables the
DHCPv4 server process on the router. The ip helper-address command is issued to enable
DHCP relay on the router. The ip dhcp pool command creates the name of a pool of addresses
that the server can assign to hosts.
10. Which kind of message is sent by a DHCP client when its IP address lease has expired?
a DHCPDISCOVER unicast message
a DHCPREQUEST broadcast message
a DHCPREQUEST unicast message
a DHCPDISCOVER broadcast message
Explanation: When the IP address lease time of the DHCP client expires, it sends a
DHCPREQUEST unicast message directly to the DHCPv4 server that originally offered the IPv4
address.
11. A host PC is attempting to lease an address through DHCP. What message is sent by the server
to let the client know it is able to use the provided IP information?
DHCPDISCOVER
DHCPOFFER
DHCPREQUEST DHCPACK
DHCPNACK
Explanation: When a host uses DHCP to automatically configure an IP address, the typically
sends two messages: the DHCPDISCOVER message and the DHCPREQUEST message.
These two messages are usually sent as broadcasts to ensure that all DHCP servers receive
them. The servers respond to these messages using DHCPOFFER, DHCPACK, and
DHCPNACK messages, depending on the circumstance.
