Exam MTCNA Topic 7 Question 18 Discussion

Routing decisions are based on the longest prefix match (i.e., the most specific subnet). First, determine which route has the most specific match for 10.1.5.126.
* Route 1: 10.1.5.0/24 # covers 10.1.5.0 to 10.1.5.255 ##Match
* Route 3: 10.1.5.0/25 # covers 10.1.5.0 to 10.1.5.127 ##Also a match and more specific
* BUT, 10.1.5.126 falls within /25 (last usable host)# So, Route 3 should be preferred due to longer prefix However, let's clarify:
If Route 3 (dst-address=10.1.5.0/25) has a next-hop (gateway) of 10.1.1.2, and if that route is reachable, it should be chosen.
Wait - it appears the answer marked in the original key might be inconsistent with routing rules.
Let's correct it:
Matching routes:
* Route 1: /24 # Prefix length: 24
* Route 3: /25 # Prefix length: 25 # More specific # Preferred#
Hence:
* 10.1.5.126 matches 10.1.5.0/25 (Route 3)
* Gateway for that = 10.1.1.2 # Correct answer: C
Corrected answer: C
MTCNA Course Manual - Routing Decision Process:
"MikroTik uses longest prefix match - the most specific (longest) subnet wins." Rene Meneses Guide - Routing Resolution:
"If multiple routes match, the one with the most specific netmask (largest prefix) is selected." Terry Combs Notes - Routing Table Evaluation:
"Router picks based on subnet specificity. /25 beats /24."