Based on the exhibit, why is the static route not being used for 172.18.9.10?
This is correct because longest-prefix match causes the connected /24 to be used for that destination.
Why this answer
The static route is not being used because the connected route is the more specific match. In practical terms, route selection starts with prefix specificity. The static route covers a broad /16, but the destination 172.18.9.10 also falls inside a connected /24. The /24 wins because it is more specific.
This is a classic routing interpretation question because it tests whether you apply longest-prefix logic before thinking about route source preference.
Exam trap
A common exam trap is assuming that static routes are always preferred over connected routes or that connected routes have a higher administrative distance. Candidates might overlook the longest-prefix match rule and focus only on administrative distance or route type. This leads to the incorrect conclusion that the static /16 route should be used for 172.18.9.10, ignoring that the connected /24 route is more specific and therefore preferred.
Misunderstanding this concept causes errors in interpreting routing tables and route selection behavior.
Why the other options are wrong
This is incorrect because static routes are still used when no connected route matches the destination. The presence of any connected route does not prevent static routes from being used if they are more specific or the only match.
This is wrong because connected routes have an administrative distance of 0, not 255. The issue here is route specificity, not administrative distance values.
This is incorrect because static routes can be configured for any prefix length, not just default routes. They are valid for specific subnets and are commonly used for precise routing control.