300-410 Layer 3 Technologies Practice Question
A network engineer is implementing policy-based routing (PBR) on a Cisco router. The goal is to forward traffic from a specific source subnet to a next-hop that is not the default gateway. The engineer configures a route map with a match statement for the source subnet and a set statement for the next-hop. However, the traffic is still following the default route. What is the most likely reason?
⚠ Common exam trap
The trap here is assuming that configuring the route map alone is sufficient for PBR, when actually it must be explicitly applied to an 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 ip policy route-map command is not configured on the ingress interface.
Policy-based routing requires the route map to be applied to the ingress interface with the ip policy route-map command. Without this command, the route map is not evaluated, and traffic is forwarded using the normal routing table, which explains why traffic follows the default route. Other issues, such as an incorrect next-hop or missing permit statement, would cause different symptoms, such as traffic being dropped or sent to the wrong next-hop, but not reverting to the default route.
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 set statement is using an incorrect next-hop address.
Why it's wrong here
If the set statement used an incorrect next-hop address, the traffic would be forwarded to that incorrect next-hop if PBR were applied. However, the traffic is following the default route, which suggests PBR is not being applied. An incorrect next-hop would not cause the traffic to revert to the default route; it would cause the traffic to be sent to the wrong next-hop or dropped. Therefore, this is not the most likely reason.
- ✗
The route map is missing a permit statement.
Why it's wrong here
If the route map is missing a permit statement, the match statement might not be evaluated correctly. However, a route map with a match statement and a set statement typically includes a permit sequence. If the route map has no permit statement, it would deny all traffic, which would cause traffic to be dropped, not follow the default route. The scenario states that traffic is following the default route, indicating that PBR is not being applied at all, rather than being applied and denying traffic.
- ✓
The ip policy route-map command is not configured on the ingress interface.
Why this is correct
For PBR to work, the route map must be applied to the ingress interface using the ip policy route-map command. If this command is missing, the route map will not be evaluated, and traffic will be forwarded based on the routing table. This is a common oversight. The engineer must enter interface configuration mode and apply the route map to the interface where traffic enters the router. Without this step, PBR will not function.
- ✗
The route map is not applied to the correct interface.
Why it's wrong here
While applying the route map to the wrong interface is a possible error, it is not the most likely reason if the engineer has already configured it. The question states that the engineer configured a route map with match and set statements, but does not specify the application. However, a more common oversight is forgetting to enable PBR on the interface with the ip policy route-map command. If the route map is not applied, PBR will not take effect. But the question implies the engineer may have applied it; the most likely reason is a missing ip policy command.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.