CCNA IP Routing Practice Question

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 most specific matching route is preferred over broader matching routes.

  Why this is correct

  Longest-prefix match (LPM) is the fundamental forwarding decision rule used by routers: when multiple routing table entries match a destination IP address, the router chooses the route with the longest subnet mask, because that route identifies the smallest, most precise address range. This ensures that a host route (/32) or a /26 will always beat a less specific /16 or default route, guaranteeing predictable path selection toward the most exact destination.

• ✓

  A /24 is more specific than a /16.

  Why this is correct

  Prefix length expresses the number of fixed network bits in the subnet mask; /24 has 24 network bits and 8 host bits, while /16 has 16 network bits and 16 host bits. Because a /24 defines a block of 256 addresses and a /16 defines a block of 65,536 addresses, the /24 falls entirely inside the /16 and is therefore much narrower in scope. In longest-prefix match, the /24's longer prefix length gives it priority whenever a destination address falls within both ranges.

• ✗

  The default route is always preferred over a matching specific route.

  Why it's wrong here

  The default route (0.0.0.0/0) has the shortest prefix length and is only used when no more specific route exists; longest-prefix match selects the route with the longest subnet mask, so a specific route always takes precedence over the default. This option is tempting because a default route acts as a catch-all for unknown destinations, but it is never preferred over a matching specific route in the forwarding decision.

  When this WOULD be correct

  In a question that asks about routing behavior in a scenario where a network is configured to prioritize default routes for certain traffic types, such as in a failover situation, this option could be correct. For example, if a default route is explicitly configured to take precedence over specific routes for redundancy purposes.

• ✗

  Administrative distance replaces the need for longest-prefix match.

  Why it's wrong here

  Administrative distance (AD) is only used to compare routes to the same destination prefix from different routing protocols or sources (e.g., a static route with AD 1 vs. OSPF with AD 110); it does not compare routes of differing prefix lengths. Longest-prefix match operates independently and first selects the route with the longest subnet mask before AD is ever considered. If AD could override LPM, routers would load-balance across or choose a less precise route, causing incorrect forwarding—so both metrics coexist in the routing decision process.

  When this WOULD be correct

  In a question that asks about route selection criteria in a routing protocol where administrative distance is the sole factor for determining route preference, this option could be correct. For example, if the question specifies that the longest-prefix match is not applicable and only administrative distance is considered, then this statement would hold true.

• ✗

  A /16 is more specific than a /24.

  Why it's wrong here

  This reverses the meaning of prefix length: a /16 actually represents a larger, less specific address range (two octets of host bits), while a /24 represents a smaller, more specific range (one octet of host bits). Treating /16 as more specific contradicts the longest-prefix rule that higher prefix bit counts define shorter, more precise network segments. For example, 192.168.1.0/24 nests within 192.168.0.0/16, so the /24 is the more specific match.

  When this WOULD be correct

  If the exam question were to ask which subnet mask is less specific in a routing context, or if it specifically stated that the context was reversed or misinterpreted, then option E could be correct. For example, a question could state, 'Which of the following is true if we consider broader ranges?'

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”