DHCP Practice Questions

Answers and explanations appear when you work through the set above.

1. Which command on a router configured as a DHCP client shows the lease details it received, including the DHCP server's address and lease timers?

   • show dhcp lease
   • show ip interface brief
   • show running-config
   • show ip route

2. An administrator wants to set up a router as a DHCP server for the 10.10.10.0/24 subnet, but reserve addresses .1 through .10 for static assignment to servers and printers. Which command reserves that range before creating the pool?

   • ip dhcp excluded-address 10.10.10.1 10.10.10.10
   • ip dhcp reserved-address 10.10.10.1 10.10.10.10
   • network 10.10.10.1 10.10.10.10 exclude
   • ip dhcp pool exclude 10.10.10.1-10.10.10.10

3. Inside an ip dhcp pool configuration, which command tells clients in that pool what default gateway address to use?

   • default-router <ip>
   • gateway <ip>
   • ip default-gateway <ip>
   • router-address <ip>

4. DHCP clients and their server are on different subnets. Routing, the server scope, and ACLs are verified, but no relay is configured on the client-facing router interface. Which change allows initial client broadcasts to reach the server?

   • DHCP cannot work across routed subnets under any circumstances
   • Routers do not forward broadcast traffic by default, so an ip helper-address command is needed on the client-facing interface to relay requests to the server
   • The DHCP server needs a static route to the client subnet instead
   • The clients need to be manually configured with the server's IP address

5. On a Cisco IOS DHCP server, which command shows which clients currently hold a leased IP address along with their hardware or client ID?

   • show ip dhcp binding
   • show dhcp lease
   • show ip dhcp pool
   • show mac address-table

6. A Windows client that previously had a DHCP-assigned address is told to release its lease. Which command does this on the client, and what happens to its addressing afterward?

   • ipconfig /release, which releases the current DHCP lease and discards the affected adapter's DHCP IPv4 configuration
   • ipconfig /flushdns, which releases the DHCP lease as well as clearing cached names
   • ipconfig /renew, which discards the lease without requesting configuration
   • netsh dhcp release, which disables the network adapter entirely

7. In an ip dhcp pool for IP phones, an engineer configures option 150 pointing to an IP address. What is this option used for?

   • It sets the DNS server address for the phones
   • It tells Cisco IP phones the address of their TFTP server so they can download their configuration files
   • It configures the default gateway for the phone subnet
   • It disables DHCP for that pool and forces static addressing

8. An administrator wants to remove an existing DHCP pool named kibria and its exclusion range entirely from the router's configuration. Which pair of commands does this?

   • delete ip dhcp pool kibria, then delete ip dhcp excluded-address
   • no ip dhcp pool kibria, and no ip dhcp excluded-address <range>
   • shutdown ip dhcp pool kibria
   • clear ip dhcp pool kibria

9. A router is configured with two separate DHCP pools, one for a PC subnet and one for a Voice VLAN subnet used by IP phones, each with a different default-router value. What determines which pool a given client's request is served from?

   • Whichever pool was configured first in the running configuration
   • The subnet of the interface the request was received on (or relayed from), since the server matches the request to the pool whose network statement contains that subnet
   • The client's MAC address vendor prefix
   • DHCP pools always serve requests round robin regardless of subnet