mediumMultiple ChoiceObjective-mapped
300-410 Practice Question: Router R3 has the following DHCP configuration:…
Router R3 has the following DHCP configuration: ip dhcp pool POOL2 network 10.10.10.0 255.255.255.0
default-router 10.10.10.1 dns-server 10.10.10.2 lease 7 !
interface GigabitEthernet0/0 ip address 10.10.10.1 255.255.255.0 ip dhcp relay information option no shutdown
What is the problem with this configuration?
⚠ Common exam trap
Cisco often tests the misconception that 'ip dhcp relay information option' is a generic DHCP feature that can be applied anywhere, when in fact it is strictly for relay agents and causes problems if enabled on a DHCP server interface.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The relay information option should not be configured on the server interface; it is intended for relay agents and may cause DHCP packets to be dropped or misprocessed.
The 'ip dhcp relay information option' command is intended for DHCP relay agents to insert Option 82 (Relay Agent Information) into DHCP packets. When configured on a DHCP server interface, it causes the server to expect and process Option 82, but since the server itself is not a relay agent, this can lead to malformed packets, dropped requests, or misprocessing of DHCP messages. In this scenario, R3 is acting as the DHCP server on GigabitEthernet0/0, so the command should be removed to ensure normal DHCP operation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The relay information option should not be configured on the server interface; it is intended for relay agents and may cause DHCP packets to be dropped or misprocessed.
Why this is correct
The ip dhcp relay information option is meant for interfaces acting as DHCP relay agents. On a server interface, it can cause the server to add Option 82 to its own packets, leading to confusion or packet rejection.
- ✗
The lease duration of 7 days is invalid; valid lease values are in hours or minutes only.
Why it's wrong here
The lease can be specified in days, hours, or minutes. A value of 7 means 7 days, which is valid.
- ✗
The default-router address is missing the subnet mask, which will cause clients to receive an incomplete configuration.
Why it's wrong here
The default-router command only requires the IP address; the subnet mask is not needed here.
- ✗
The DNS server address is on the same subnet as the clients, which is not allowed.
Why it's wrong here
The DNS server can be on the same subnet; there is no restriction against it.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.