FPDNS(1)

🌸 NAME 🌸

This is fpdns(1), a User Contributed Perl Documentation page for fpdns, aka the DNS server fingeprinting tool. Yes, “fingeprinting” — that is literally the NAME spelling, and we are keeping it exactly. 💅

✨ SYNOPSIS ✨

fpdns [ -d ] [ -f ] [ -F nchild ]
   [ -p port ] [ -Q srcaddr ] [ -r retry ]
   [ -s ]  [ -S separator ] [ -t timeout ] [ -v ] [server(s)]

💖 DESCRIPTION 💖

Okay so fpdns is a program that remotely determines DNS server versions. It does this by sending a series of borderline DNS queries which are compared against a table of responses and server versions. No cap, that’s the whole flex. 🦋

Heads up, bestie: False positives or incorrect versions may be reported when trying to identify a set of servers residing behind a load-balancing apparatus where the servers are of different implementations, when a specific implementation behaves like a forwarder, behind a firewall without statefull inspection or without Application Intelligence. That is the exact caveat, and it is not a drill. 😭

🎀 OPTIONS 🎀

One bullet per flag, all facts intact, let’s go 💖

• -d — Enable debugging. Off by default.
• -D — Check all authoritative servers of the specified domain name.
• -f — Force checking of CH TXT version. Off by default.
• -F nchild — Maximum number of forked child processes. Defaults to 10.
• -p port — Port to query remote nameserver on. Default is 53.
• -Q srcaddr — Set the source IP address to use.
• -r retry — Number of attempt to retry fingerprints. Defaults to 1.
• -s — Short display form. Useful for surveys.
• -S separator — Separator. Defaults to " ".
• -t timeout — Set the query timeout in seconds. Defaults to 5.
• -T — Use TCP instead of UDP.
• -v — Show version of fpdns.
• server — IP address or name to query. Alternatively may be '-' to read from a list of these from stdin.

🦋 AUTHORS 🦋

fpdns was written by Roy Arends and Jakob Schlyter. Iconic duo behavior, honestly. 👑

🔥 SEE ALSO 🔥

perl(1), Net::DNS(1) — go peek at these too, bestie. 🌈

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And that’s the whole page, babes: it comes from perl v5.40.0, dated 2024-11-26. Mwah 💋