Script fcrdns

Script types: hostrule
Categories: discovery, safe
Download: https://svn.nmap.org/nmap/scripts/fcrdns.nse

Script Summary

Performs a Forward-confirmed Reverse DNS lookup and reports anomalous results.

References:

• https://en.wikipedia.org/wiki/Forward-confirmed_reverse_DNS

Example Usage

nmap -sn -Pn --script fcrdns <target>

Script Output

Host script results:
|_fcrdns: FAIL (12.19.29.17, 12.19.20.14, 23.10.13.25)

Host script results:
|_fcrdns: PASS (37.58.100.86-static.reverse.softlayer.com)

Host script results:
| fcrdns:
|   <none>:
|     status: fail
|_    reason: No PTR record

Host script results:
| fcrdns:
|   mail.example.com:
|     status: fail
|     reason: FCRDNS mismatch
|     addresses:
|       12.19.29.17
|   mail.contoso.net:
|     status: fail
|     reason: FCRDNS mismatch
|     addresses:
|       12.19.20.14
|_      23.10.13.25

Requires

• dns
• ipOps
• nmap
• stdnse
• string
• table
• tableaux

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Author:

• Daniel Miller

License: Same as Nmap--See https://nmap.org/book/man-legal.html