fpdns(1) DNS server fingeprinting tool


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


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.

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.


Enable debugging. Off by default.
Check all authoritative servers of the specified domain name.
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.
Short display form. Useful for surveys.
Separator. Defaults to `` ''.
-t timeout
Set the query timeout in seconds. Defaults to 5.
Use TCP instead of UDP.
Show version of fpdns.
IP address or name to query. Alternatively may be '-' to read from a list of these from stdin


fpdns was written by Roy Arends and Jakob Schlyter.