In a stub network, what condition typically necessitates a default route?

• A. There is only a single exit path to reach other networks.
• B. There are multiple exit paths to external networks.
• C. The network uses only static routes.
• D. There is no route learning.

Answer: (A)

In a network, a stub network has only one exit to the rest of the network, so any traffic destined for outside destinations must be forwarded through that single gateway. A default route serves as a catch-all for destinations not listed in the local routing table, directing all such traffic to that one exit point. That single exit path is exactly what makes a default route both practical and sufficient in a stub network. If there were multiple exits, you’d need more specific routing or policies instead of a single default route. The presence of static routes or the absence of route learning isn’t the defining factor here; the key idea is having one exit path to reach external networks.