If a forward zone has no configured forwarders, what is the likely outcome?

• A. The server may attempt to resolve using its own resolver or fail depending on recursion settings
• B. It will automatically become authoritative
• C. It will always return an NXDOMAIN
• D. It will forward to root servers automatically

Answer: (A)

At the heart of this is how DNS resolution works when there are no upstream forwarders defined for a zone. A forward zone directs queries to upstream resolvers, but if none are configured, the server must decide how to handle those lookups based on its recursion setting.

If recursion is enabled on the server, it will perform recursive resolution on its own. That means it will query root servers and then authoritative servers as needed to obtain the final answer, effectively acting as its own recursive resolver for that zone. If recursion is disabled, the server cannot fetch answers from the wider DNS hierarchy and will typically fail to resolve queries it cannot answer from cache or the zone data, producing an error rather than a successful answer.

This is why the described outcome is that the server may attempt to resolve using its own resolver or fail depending on recursion settings. The other options don’t fit: it won’t automatically become authoritative merely because there are no forwarders, and NXDOMAIN isn’t guaranteed in the absence of forwarders or recursion (it depends on whether the server can resolve the name). It also won’t automatically forward to root servers unless recursion is effectively enabled, which is handled by the server’s resolver rather than a separate “forward to root” action.