If an NFS client can mount the FA File export shares with the IP address,...

When an NFS client successfully mounts an export using the target ' s IP address, it proves that the fundamental network connectivity (routing, firewalls) and the storage protocol layer (NFS export policies, host access permissions) are functioning correctly.

However, if the exact same mount attempt fails when using the Fully Qualified Domain Name (FQDN) of the FlashArray file service, the issue lies entirely with name resolution. The Domain Name System (DNS) is responsible for translating human-readable FQDNs into the IP addresses required for network communication. If the client cannot reach the DNS server, or if the DNS server lacks the correct A or AAAA records for the FlashArray ' s file Virtual IP (VIP) addresses, the client won ' t be able to resolve the name to the IP, causing the mount command to fail.

Here is why the other options are incorrect:

Issue with the Active Directory (AD) controller (A): Active Directory is primarily used for directory services, user authentication, and authorization (such as mapping permissions for SMB or NFSv4). While AD environments usually include DNS, an " AD controller issue " in the context of storage protocols usually points to permission denials, not host name resolution failures. Furthermore, since the mount works via IP, basic access is already validated.

Issue with the OpenLDAP (C): Similar to AD, OpenLDAP provides directory services for user mappings (UID/GID) and authentication. It does not perform FQDN-to-IP resolution.