Courseiva
← 200-301
Full test
hardmultiple choiceObjective-mapped

Exhibit

interface vlan 30
 ip address 10.30.30.1 255.255.255.0
 no shutdown

DHCP server: 10.99.99.20

Exhibit: A DHCP client on VLAN 30 is not receiving an address from a server located on another subnet. The SVI configuration is shown below. What should be added?

Question 1hardmultiple choice
Full question →

Exhibit: A DHCP client on VLAN 30 is not receiving an address from a server located on another subnet. The SVI configuration is shown below. What should be added?

Full question →

Answer choices

Why each option matters

Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.

A

Distractor review

ip directed-broadcast 10.99.99.20

That is unrelated and not used for DHCP relay.

B

Best answer

ip helper-address 10.99.99.20

The helper address forwards DHCP broadcasts as unicast to the server.

C

Distractor review

service dhcp-server 10.99.99.20

That is not the Cisco IOS interface command for relay.

D

Distractor review

default-router 10.99.99.20

That is a DHCP pool parameter, not an SVI relay command.

Common exam trap

Common exam trap: answer the scenario, not the keyword

A frequent exam trap is selecting ip directed-broadcast or default-router as the solution for DHCP relay issues. ip directed-broadcast only enables forwarding of directed broadcasts but does not relay DHCP requests to servers on other subnets. default-router is a DHCP pool parameter that assigns a gateway to clients but does not affect how DHCP broadcasts are forwarded. Another trap is assuming service dhcp-server is an interface command for relay, which it is not. These distractors test your understanding of DHCP relay mechanisms and Cisco IOS command usage.

Technical deep dive

How to think about this question

Dynamic Host Configuration Protocol (DHCP) clients initially send DHCP Discover messages as broadcasts to locate available DHCP servers. Because routers do not forward broadcast traffic by default, clients on one VLAN or subnet cannot directly communicate with DHCP servers on another subnet. This behavior ensures broadcast containment but requires a relay mechanism for DHCP to function across routed boundaries. To enable DHCP clients on VLAN 30 to receive IP addresses from a DHCP server on a different subnet, the router interface connected to VLAN 30 must be configured with the ip helper-address command pointing to the DHCP server's IP address. This command instructs the router to intercept DHCP broadcast messages and forward them as unicast packets to the specified DHCP server, effectively bridging the broadcast domain gap. The SVI configuration must include this command to relay DHCP requests properly. A common exam trap is confusing ip helper-address with other interface commands like ip directed-broadcast or DHCP pool parameters such as default-router. While ip directed-broadcast enables forwarding of directed broadcasts, it does not relay DHCP requests. Similarly, default-router is a DHCP pool setting that provides clients with a gateway address but does not influence relay behavior. Understanding this distinction is critical for correctly configuring DHCP relay in Cisco environments and ensuring clients receive IP addresses across VLANs.

KKey Concepts to Remember

  • DHCP clients send broadcast messages that do not cross router interfaces without specific relay configuration.
  • The ip helper-address command on an SVI or routed interface forwards DHCP broadcasts as unicast packets to a DHCP server on a different subnet.
  • Without ip helper-address, DHCP Discover messages from clients on VLANs cannot reach DHCP servers located on other subnets.
  • The ip directed-broadcast command enables forwarding directed broadcasts but does not facilitate DHCP relay functionality.
  • DHCP pool parameters like default-router configure client options but do not affect DHCP relay behavior on interfaces.
  • Cisco IOS does not use a service dhcp-server command on interfaces to enable DHCP relay; ip helper-address is required.
  • An SVI (Switched Virtual Interface) acts as a Layer 3 interface for VLANs and must be configured with ip helper-address to relay DHCP requests.
  • DHCP relay via ip helper-address converts client broadcasts into unicast packets directed to the DHCP server IP address.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

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More questions from this exam

Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.

Question 1

A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?

Question 2

A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?

Question 3

What is the OSPF metric called?

Question 4

A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?

Question 5

A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?

Question 6

A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?

FAQ

Questions learners often ask

What does this 200-301 question test?

DHCP clients send broadcast messages that do not cross router interfaces without specific relay configuration.

What is the correct answer to this question?

The correct answer is: ip helper-address 10.99.99.20 — DHCP Discover messages are broadcasts and do not cross routers by default. On an SVI or routed interface facing the clients, an ip helper-address relays those broadcasts to the DHCP server on another subnet.

What should I do if I get this 200-301 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.

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