PCNSE Core Concepts and Architecture Practice Question
Exhibit
Refer to the exhibit. ``` admin@PA-5050> show routing route IPv4 Virtual Router: default destination nexthop interface metric flags 0.0.0.0/0 10.0.0.1 ethernet1/1 10 A S 10.0.0.0/8 10.0.0.1 ethernet1/1 10 A S 10.0.0.0/24 10.0.0.2 ethernet1/2 10 A S 10.0.1.0/24 10.0.0.3 ethernet1/3 10 A S 172.16.0.0/12 10.0.0.4 ethernet1/4 10 A S 192.168.0.0/16 10.0.0.5 ethernet1/5 10 A S ```
A firewall has the routing table shown. A packet arrives on ethernet1/2 with source IP 10.0.0.50 and destination IP 10.0.0.100. Which route will be used for forwarding?
⚠ Common exam trap
The trap here is that candidates often pick the default route or the classful /8 route without considering the longest-prefix match rule, mistakenly assuming that a broader match or the default route is sufficient for forwarding.
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
✓
10.0.0.0/24 via 10.0.0.2 ethernet1/2
The firewall performs a longest-prefix match on the routing table. The destination IP 10.0.0.100 matches the 10.0.0.0/24 route (prefix length 24) more specifically than the 10.0.0.0/8 route (prefix length 8) or the default route. Since the packet arrived on ethernet1/2 and the matching route points to the same interface, the route via 10.0.0.2 ethernet1/2 is selected.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
10.0.0.0/24 via 10.0.0.2 ethernet1/2
Why this is correct
Longest prefix match: /24 is more specific than /8.
- ✗
10.0.1.0/24 via 10.0.0.3 ethernet1/3
Why it's wrong here
Destination 10.0.0.100 is not in 10.0.1.0/24.
- ✗
10.0.0.0/8 via 10.0.0.1 ethernet1/1
Why it's wrong here
The /8 route is less specific than the /24 route.
- ✗
0.0.0.0/0 via 10.0.0.1 ethernet1/1
Why it's wrong here
Default route is least specific.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCNSE practice question is part of Courseiva's free Palo Alto Networks 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 PCNSE exam.