The security team for Company XYZ has determined that someone from outside the organization has obtained sensitive information about the internal organization by querying the external DNS server of…

Implementing split DNS where the external DNS server contains only records for publicly facing hosts ensures that external parties cannot query and map internal hostnames, IP addresses, or services. The internal DNS zone retains full records for internal resolution, while the external zone is scoped to only what is necessary for outside access. This directly closes the reconnaissance vector described in the scenario.

This choice continues exposing more information than necessary on the external DNS server, failing to resolve the information leakage problem the security manager was tasked to fix.

Restricting only the internal DNS server does not address the root cause, since it is the external DNS server being queried by outsiders that is leaking sensitive organizational data.

Placing information only on the internal DNS server without also limiting the external DNS server to public records leaves the external server able to expose sensitive details to outside queries.