Nmap dns-nsid NSE Script


This page contains detailed information about how to use the dns-nsid NSE script. For list of all NSE scripts, visit the Nmap NSE Library.

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Overview
Error Messages

Script Overview

Script source code: https://github.com/nmap/nmap/tree/master/scripts/dns-nsid.nse
Script categories: discovery, default, safe
Target service / protocol: dns, udp, tcp
Target network port(s): 53
List of CVEs: -

Script Description

The dns-nsid.nse script retrieves information from a DNS nameserver by requesting its nameserver ID (nsid) and asking for its id.server and version.bind values. This script performs the same queries as the following two dig commands:

  • dig CH TXT bind.version @target
  • dig +nsid CH TXT id.server @target

References:

  1. http://www.ietf.org/rfc/rfc5001.txt
  2. http://www.ietf.org/rfc/rfc4892.txt

Dns-nsid NSE Script Arguments

The dns-nsid.nse script does not have any arguments.

Dns-nsid NSE Script Example Usage

Here's an example of how to use the dns-nsid.nse script:

nmap -sSU -p 53 --script dns-nsid <target>

Dns-nsid NSE Script Example Output

Here's a sample output from the dns-nsid.nse script:

53/udp open  domain  udp-response
| dns-nsid:
|   NSID dns.example.com (646E732E6578616D706C652E636F6D)
|   id.server: dns.example.com
|_  bind.version: 9.7.3-P3

Dns-nsid NSE Script Example XML Output

Here's a sample XML output from the dns-nsid.nse script produced by providing the -oX <file> Nmap option:

 <table key="NSID">
   <elem key="raw">mia01.l.root-servers.org</elem>
   <elem key="hex">6d696130312e6c2e726f6f742d736572766572732e6f7267</elem>
 </table>
 <elem key="id.server">mia01.l.root-servers.org</elem>
 <elem key="bind.version">NSD 3.2.15</elem>

Author

  • John R. Bond

References

See Also

Related NSE scripts to the dns-nsid.nse script:

Visit Nmap NSE Library for more scripts.

The dns-nsid.nse script may fail with the following error messages. Check for the possible causes by using the code snippets highlighted below found in the script source code. This can often times help in identifying the root cause of the problem.

Failed to decode NSID

Here is a relevant code snippet related to the "Failed to decode NSID" error message:

59:	local function rr_filter(pktRR, label)
60:	  for _, rec in ipairs(pktRR, label) do
61:	    if ( rec[label] and 0 < #rec.data ) then
62:	      if ( dns.types.OPT == rec.dtype ) then
63:	        if #rec.data < 4 then
64:	          return false, "Failed to decode NSID"
65:	        end
66:	        local _, len, pos = string.unpack(">I2 I2", rec.data)
67:	        if ( len ~= #rec.data - pos + 1 ) then
68:	          return false, "Failed to decode NSID"
69:	        end

Failed to decode NSID

Here is a relevant code snippet related to the "Failed to decode NSID" error message:

63:	        if #rec.data < 4 then
64:	          return false, "Failed to decode NSID"
65:	        end
66:	        local _, len, pos = string.unpack(">I2 I2", rec.data)
67:	        if ( len ~= #rec.data - pos + 1 ) then
68:	          return false, "Failed to decode NSID"
69:	        end
70:	        return true, string.unpack("c" .. len, rec.data, pos)
71:	      else
72:	        return true, string.unpack(">s1", rec.data)
73:	      end

Version

This page has been created based on Nmap version 7.92.

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