Product and Software: This article applies to all Aruba controllers and ArubaOS versions.
If the controller is isolated from the network and any client tries to resolve the FQDN name, the controller resolves any FQDN and returns its own IP address. This action does not mean that the controller is acting as a DNS server.
Normal DNS servers forward the queries to the root server and respective name servers for address resolution. The Aruba controller does not do that, but it responds with its own IP address for every FQDN that is queried.
The Aruba controller performs a DNS inspection process because the Aruba code provides captive portal functionality. Aruba controllers should redirect users to our captive portal based on the inspection of the DNS queries. When it receives any DNS queries, it will return the controller address.
This functionality is intended for the captive portal function and any other switches will not have this functionality. Any other switch will not return its own address for a DNS query. This functionality is done mainly to provide the captive portal to users, possible only through DNS inspection. This is designed in architecture of the code.