Nmap --dns-servers

When scanning my local network I can use the --dns-servers switch to specify the router (BThub in this case) as the DNS server which will then list online devices and their network hostname. Without this switch it just displays IP addresses.

When performing this same scan on a different LAN this time selecting the Virgin Hub as the --dns-server it doesn’t resolve hostnames.

Interestingly I can use the Fing scanner on my iPhone to resolve the hostnames of the connected devices on both networks

I’ve tried various scan techniques in Nmap but still no luck. I’m wondering how Fing manages to do it and how I can get Nmap to produce the same results.