Didier Stevens

dns-query-async.py is a tool to perform DNS queries in parallel.

This is the man page:

Usage: dns-query-async.py [options] command file
Program to perform asynchronous DNS queries

accepted commands: gethost,getaddr

Source code put in the public domain by Didier Stevens, no Copyright
Use at your own risk
https://DidierStevens.com

Options:
  --version             show program's version number and exit
  -h, --help            show this help message and exit
  -m, --man             Print manual
  -o OUTPUT, --output=OUTPUT
                        Output to file (# supported)
  -s NAMESERVERS, --nameservers=NAMESERVERS
                        List of nameservers (,-separated)
  -n NUMBER, --number=NUMBER
                        Number of simultaneous requests (default 10000)
  -t TRANSFORM, --transform=TRANSFORM
                        Transform input (%%)

Manual:

This tool performs asynchronous DNS queries. By default, it will perform 10000
queries simultaneously.

The first argument is a command. There are 2 commands for the moment: gethost
and getaddr
The second argument is a filename: a text file containing the items to resolve.

Use command getaddr to lookup the IP address of the hostnames provided in the
input file.
Example:
 dns-query-async.py getaddr names.txt
Result:
 didierstevens.com,1,96.126.103.196
 didierstevenslabs.com,1,96.126.103.196
 Duration: 0.20s

Use command gethost to lookup the hostnames of the IP addresses provided in the
input file.
Example:
 dns-query-async.py gethost ips.txt

Use option -s to provide the name servers to use (comma separated list).

Use option -n to change the number of asyncio workers (10000 default).

Use option -t to transform the input list and perform lookups.
For example, take list of subdomains/hostnames https://github.com/m0nad/DNS-
Discovery/blob/master/wordlist.wl
Issue the following command:
 dns-query-async.py -t %%.example.com getaddr wordlist.wl
Result:
 0.example.com,0,Domain name not found
 009b.example.com,0,Domain name not found
 01.example.com,0,Domain name not found
 02.example.com,0,Domain name not found
 03.example.com,0,Domain name not found
 1.example.com,0,Domain name not found
 10.example.com,0,Domain name not found
 101a.example.com,0,Domain name not found

The %% in %%.example.com is replaced by each hostname/subdomain in wordlist.wl
and then resolved.

Use option -o to write the output to a file.