DHCP Questions

Question 6 Which type of information resides on a DHCP server? A. a list of the available IP addresses in a pool B. a list of public IP addresses and their corresponding names C. usernames and passwords for the end users in a domain D. a list of statically assigned MAC addresses

A

Question 7 What is a DHCP client? A. a host that is configured to request an IP address automatically B. a router that statically assigns IP addresses to hosts C. a server that dynamically assigns IP addresses to hosts D. a workstation that requests a domain name associated with its IP address

A

Question 8 Where does the configuration reside when a helper address is configured to support DHCP? A. on the switch trunk interface B. on the router closest to the client. C. on the router closest to the server. D. on every router along the path.

B

Question 4 Refer to the exhibit. An engineer deploys a topology in which R1 obtains its IP configuration from DHCP. If the switch and DHCP server configurations are complete and correct. Which two sets of commands must be configured on R1 and R2 to complete the task? (Choose two) A. R1 (config)# interface fa0/0R1 (config-if)# ip helper-address 198.51.100.100 B. R2(config)# interface gi0/0R2(config-if)# ip helper-address 198.51.100.100 C. R1 (config)# interface fa0/0R1 (config-if)# ip address dhcpR1 (config-if)# no shutdown D. R2(config)# interface gi0/0R2(config-if)# ip address dhcp E. R1 (config)# interface fa0/0R1 (config-if)# ip helper-address 192.0.2.2

B C

Question 10 Which command must you enter to configure a DHCP relay? A. ip helper-address B. ip address dhcp C. ip dhcp relay D. ip dhcp pool

A Explanation If the DHCP Server is not on the same subnet with the DHCP Client, we need to configure the router on the DHCP client side to act as a DHCP Relay Agent so that it can forward DHCP messages between the DHCP Client & DHCP Server. To make a router a DHCP Relay Agent, simply put the "ip helper-address <IP-address-of-DHCP-Server>" command under the interface that receives the DHCP messages from the DHCP Client. As we know, router does not forward broadcast packets (it drops them instead) so DHCP messages like DHCPDISCOVER message will be dropped. But with the "ip helper-address ..." command, the router will accept that broadcast message and cover it into a unicast packet and forward it to the DHCP Server. The destination IP address of the unicast packet is taken from the "ip helper-address ..." command.

Question 2 Which command enables a router to become a DHCP client? A. ip address dhcp B. ip helper-address C. ip dhcp pool D. ip dhcp client

A Explanation If we want to get an IP address from the DHCP server on a Cisco device, we can use the command "ip address dhcp". Note: The command "ip helper-address" enables a router to become a DHCP Relay Agent.

Question 3 What are two roles of the Dynamic Host Configuration Protocol (DHCP)? (Choose two) A. The DHCP server offers the ability to exclude specific IP addresses from a pool of IP addresses B. The DHCP client can request up to four DNS server addresses C. The DHCP server assigns IP addresses without requiring the client to renew them D. The DHCP server leases client IP addresses dynamicallyE. The DHCP client maintains a pool of IP addresses it can assign

A D

Question 11 Where does a switch maintain DHCP snooping information? A. in the CAM table B. in the VLAN database C. in the DHCP binding database D. in the MAC address table

C

Question 5 Refer to the exhibit. If the network environment is operating normally, which type of device must be connected to interface FastEthernet 0/1? ip arp inspection vlan 2-10interface fastethernet 0/1ip arp inspection trust A. DHCP client B. access point C. router D. PC

C Explanation To configure DHCP snooping feature, at least three steps must be done: Sequence and DescriptionCommand1. Configure global DHCP snoopingSwitch(config)# ip dhcp snooping2. Configure trusted ports (as least on 1 port).By default, all ports are untrustedSwitch(config-if)# ip dhcp snooping trust3. Configure DHCP snooping for the selected VLANsSwitch(config)# ip dhcp snooping vlan {VLAN-ID | VLAN range} Note: To configure DHCP snooping with Dynamic ARP Inspection we need to add the command "ip arp inspection vlan vlan-id" in global configuration mode and "ip arp inspection trust" in interface mode. In a normal network environment, we should trust interfaces that are connected to routers, not end points.

Question 9 When implementing a router as a DHCP server, which two features must be configured? (Choose two) A. relay agent information B. database agent C. address pool D. smart-relayE. manual bindings

C E Explanation The following example shows how to configure a DHCP Server on a Cisco router: ConfigurationDescriptionRouter(config)#ip dhcp pool CLIENTSCreate a DHCP Pool named CLIENTSRouter(dhcp-config)#network 10.1.1.0 /24Specifies the subnet and mask of the DHCP address poolRouter(dhcp-config)#default-router 10.1.1.1Set the default gateway of the DHCP ClientsRouter(dhcp-config)#dns-server 10.1.1.1Configure a Domain Name Server (DNS)Router(dhcp-config)#domain-name 9tut.comConfigure a domain-nameRouter(dhcp-config)#lease 0 12Duration of the lease (the time during which a client computer can use an assigned IP address). The syntax is "lease {days[hours] [minutes] | infinite}". In this case the lease is 12 hours. The default is a one-day lease.Before the lease expires, the client typically needs to renew its address lease assignment with the serverRouter(dhcp-config)#exit Router(config)# ip dhcp excluded-address 10.1.1.1 10.1.1.10The IP range that a DHCP Server should not assign to DHCP Clients. Notice this command is configured under global configuration mode Manual bindings are IP addresses that have been manually mapped to the MAC addresses of hosts that are found in the DHCP database. All DHCP clients send a client identifier (DHCP option 61) in the DHCP packet. To configure manual bindings, you must enter the client-identifier DHCP pool configuration command with the appropriate hexadecimal values identifying the DHCP client. For example: ip dhcp pool SERVERhost 172.16.200.100 255.255.255.0client-identifier 01aa.bbcc.0003.00default-router 172.16.200.1! Therefore two requirements for DHCP binding is the IP address and the hardware address (MAC address) of the client. Notice that in the above example "aabb.cc00.0300" is the MAC address of the client while prefix "01" represents the Ethernet media type. Note: In fact, this question should ask "When implementing a router as a DHCP server, which one of these features must be configured?". Because we only need to configure either an "address pool" or "manual binding". Question 10

Question 1 Which Cisco IOS command will indicate that interface GigabitEthernet 0/0 is configured via DHCP? A. show ip interface GigabitEthernet 0/0 dhcp B. show interface GigabitEthernet 0/0 C. show ip interface dhcp D. show ip interface GigabitEthernet 0/0 E. show ip interface GigabitEthernet 0/0 brief

D