What Does Default Route Mean in 200-301?
Also known as: gateway of last resort, quad-zero route
Quick Definition
A catch-all route (0.0.0.0/0) used when no more-specific route exists in the routing table.
Full Definition
The default route, written as 0.0.0.0/0 (or ::/0 for IPv6), matches any destination. It is the lowest-priority route in the routing table because it has the shortest prefix length (/0). Routers use longest prefix match to select routes — a more specific route always wins over the default. A default route is typically configured on the edge router pointing toward the Internet. It can be a static route or redistributed from a routing protocol.
CLI Command
ip route 0.0.0.0 0.0.0.0 10.0.0.1 ! static default route ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0
Exam Trap — Don't Get Fooled
OSPF does not automatically advertise a default route. You must use 'default-information originate' to inject a default route into OSPF. The 'always' keyword advertises it even if no default route exists in the routing table.
Related 200-301 Terms
A link-state routing protocol that calculates the best path using cost based on bandwidth.
A value (0–255) that tells a router how trustworthy a routing source is when multiple sources advertise the same prefix.
A manually configured route that does not update automatically when the network changes.
Frequently Asked Questions
What does Default Route mean on the 200-301 exam?
The default route, written as 0.0.0.0/0 (or ::/0 for IPv6), matches any destination. It is the lowest-priority route in the routing table because it has the shortest prefix length (/0). Routers use longest prefix match to select routes — a more specific route always wins over the default. A default route is typically configured on the edge router pointing toward the Internet. It can be a static route or redistributed from a routing protocol.
How does Default Route appear as a trap on the 200-301?
OSPF does not automatically advertise a default route. You must use 'default-information originate' to inject a default route into OSPF. The 'always' keyword advertises it even if no default route exists in the routing table.
How important is Default Route on the 200-301 exam?
Default Route falls under the Routing domain of the 200-301 exam. Understanding it in context with related terms like static-route and administrative-distance is essential for answering scenario-based questions correctly.