LPIC-2 Longest Prefix Match Practice Question
Exhibit
Refer to the exhibit. ``` # ip route show table 100 192.168.10.0/24 dev eth0 scope link 0.0.0.0/1 via 10.0.0.1 dev eth1 ``` ``` # ip rule show 0: from all lookup local 32765: from 192.168.10.0/24 lookup 100 32766: from all lookup main 32767: from all lookup default ```
Given the exhibited routing table and rules, what will happen to a packet originating from IP 192.168.10.50 destined to 8.8.8.8?
⚠ Common exam trap
The trap is that candidates assume the main routing table's default route is used, ignoring policy routing rules that direct traffic to a different table with a more specific route. They may also overlook that 8.8.8.8 is within the /1 prefix range.
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 packet is forwarded via eth1 to 10.0.0.1.
The packet from 192.168.10.50 to 8.8.8.8 is processed using policy routing rules. A rule matches the source and directs the lookup to routing table 100, which contains a route 0.0.0.0/1 via eth1 with next-hop 10.0.0.1. Since 8.8.8.8 falls within the 0.0.0.0/1 prefix (0.0.0.0–127.255.255.255), the kernel selects this route and forwards the packet via eth1 to 10.0.0.1, making option C correct. Option B is incorrect because it omits the next-hop and implies the /1 route is in the main table, which it is not.
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 packet is dropped because no matching route exists.
Why it's wrong here
There is a default route in table 100, so the packet is not dropped.
- ✗
The packet is forwarded via eth1 because of the 0.0.0.0/1 route.
Why it's wrong here
The route 0.0.0.0/1 covers 8.8.8.8, but it is not a default route; the default route via 10.0.0.1 is used.
- ✓
The packet is forwarded via eth1 to 10.0.0.1.
Why this is correct
Table 100 has a default route via 10.0.0.1 for this source.
- ✗
The packet is forwarded via eth0 to the default gateway in the main table.
Why it's wrong here
The rule for this source uses table 100, not the main table.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-2 practice question is part of Courseiva's free LPI 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 LPIC-2 exam.