Referral Whois — a whois variant that hands you a pointer to the server holding the real answer.
RWhois, specified in RFC 2167, extends the whois model with hierarchy: a query that a server cannot answer comes back as a referral to the server that can, which is how regional registries delegate detail for delegated IP blocks. Servers greet with a version banner such as %rwhois V-1.5 before any query. Most surviving deployments are ISPs and hosting providers publishing SWIP-style reassignment data for their address space.
Fine to expose
It is a public directory service by design and carries no credentials; the only real concern is the contact detail you choose to publish in it.
$ nc -w 3 TARGET 4321 < /dev/null | head -1Seen this on your network? Beige Box scans your Wi-Fi and shows every open port on every device — and its Ports tool links straight back here.
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