Ccna certification Practice Tests

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Appendix 

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  Answers to Practice Test Questions

 63.  D.  The command 

ip helper-address 10.10.1.101 will configure the interface to 

become a DHCP relay agent. This command must be configured on the interface in which 

you want the DHCP relay agent to listen and respond. The command 

ip dhcp server 

10.10.1.101 configured in the global configuration prompt is incorrect. The command ip 

dhcp server 10.10.1.101 configured in the interface configuration prompt is incorrect. 

The command 

ip relay-agent 10.10.1.101 is incorrect.

 64.  B.  The Gateway Address (GIADDR) field is filled out by the DHCP relay agent before 

the DHCP packet is sent to the DHCP server. This field helps the DHCP server decide 

which scope to send an Offer message back for. The CIADDR field is used for the client 

IP address and not used to determine scope selection. The SIADDR field is used for the 

server IP address and not used to determine scope selection. The CHADDR is the client 

hardware address and not used to determine scope selection.

 65.  D.  A DHCP relay agent installed on Router A interface Gi0/0 will allow clients on Host 

A’s network to obtain IP addressing from DHCP. A second DHCP server on the network 

where Host A is located will not satisfy the requirement of using the existing DHCP 

server. A DHCP relay agent on the interface Gi0/0 located on Router B will not help serve 

IP addresses on the Host A network. A DHCP relay agent cannot be configured on a layer 

2 switch.

 66.  C.  The command 

debug ip dhcp server packet will show the details of a DHCP relay 

agent conversation. It will detail conversation between the client and router and the router 

and the DHCP server. The command 

debug dhcp is incorrect. The command show ip 

dhcp detail is incorrect. The command debug ip dhcp is incorrect.

 67.  C.  Stateless Address Autoconfiguration (SLAAC) allows for the client to learn the 

network ID and calculate a host ID that is unique. However, SLAAC lacks the ability to 

configure options such as DNS time servers, etc. DHCPv6 allows for the configuration of 

these options when used in conjunction with SLAAC. DHCPv6 configured for SLAAC 

is not used for stateful configuration of client IPv6 addressing. DHCPv6 configured for 

SLAAC will not provide network IDs. IPv6 by default provides stateless configuration of 

clients with IPv6 addressing; DHCPv6 complements this stateless configuration.

 68.  D.  They will lose their IP addresses after their entire lease has expired. Until the lease 

expires, they will have functioning IP addresses. Clients will not lose their IP addresses 

immediately because the server is only needed for renewals after the initial IP address 

lease is obtained. The host requests a renewal for the lease at one-half of the lease time, 

but if a response is not heard, the host will retain its original lease. After seven-eighths of 

the lease time, the host will attempt to find a new server to rebind the original lease of the 

IP address. If a rebind does not occur, the IP address will remain active until the end of 

the lease.

 69.  A.  Stateful DHCPv6 supplies the network ID and host ID. The default router is discovered 

through the Neighbor Discovery Protocol (NDP). Stateful DHCPv6 only supplies the 

network ID and host ID to the client; the default router is also discovered through the 

Neighbor Discovery Protocol. IPv6 uses multicasts, not broadcasts, to communicate. 

Stateful DHCPv6 is a replacement for the process of Stateless Address Autoconfiguration 

(SLAAC).

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Chapter 4: IP Services (Domain 4)