Fast and multi-purpose DNS toolkit allow to run multiple DNS queries.

Features • Installation • Usage • Running dnsx • Wildcard • Notes • Join Discord

dnsx is a fast and multi-purpose DNS toolkit allow to run multiple probes using retryabledns library, that allows you to perform multiple DNS queries of your choice with a list of user supplied resolvers, additionally supports DNS wildcard filtering like shuffledns.

Features

• Simple and Handy utility to query DNS records.
• Supports A, AAAA, CNAME, PTR, NS, MX, TXT, SOA
• Supports DNS Status Code probing
• Supports DNS Tracing
• Handles wildcard subdomains in automated way.
• Stdin and stdout support to work with other tools.

Installation Instructions

dnsx requires go1.17 to install successfully. Run the following command to get the repo -

go install -v github.com/projectdiscovery/dnsx/cmd/dnsx@latest

Usage

dnsx -h

This will display help for the tool. Here are all the switches it supports.

INPUT:
   -l, -list string  File input with list of sub(domains)/hosts

QUERY:
   -a      Query A record (default)
   -aaaa   Query AAAA record
   -cname  Query CNAME record
   -ns     Query NS record
   -txt    Query TXT record
   -ptr    Query PTR record
   -mx     Query MX record
   -soa    Query SOA record

FILTERS:
   -resp               Display DNS response
   -resp-only          Display DNS response only
   -rcode, -rc string  Display DNS status code (eg. -rcode noerror,servfail,refused)

RATE-LIMIT:
   -t, -c int            Number of concurrent threads to use (default 100)
   -rl, -rate-limit int  Number of DNS request/second (disabled as default) (default -1)

OUTPUT:
   -o, -output string  File to write output (optional)
   -json               Write output in JSONL(ines) format

DEBUG:
   -silent       Show only results in the output
   -v, -verbose  Verbose output
   -raw, -debug  Display RAW DNS response
   -stats        Display stats of the running scan
   -version      Show version of dnsx

OPTIMIZATION:
   -retry int                Number of DNS retries (default 1)
   -hf, -hostsfile           Parse system host file
   -trace                    Perform DNS trace
   -trace-max-recursion int  Max recursion for dns trace (default 32767)
   -flush-interval int       Flush interval of output file (default 10)
   -resume                   Resume

CONFIGURATIONS:
   -r, -resolver string          List of resolvers (file or comma separated)
   -wt, -wildcard-threshold int  Wildcard Filter Threshold (default 5)
   -wd, -wildcard-domain string  Domain name for wildcard filtering (other flags will be ignored)

Running dnsx

dnsx can be used to filter dead records from the list of passive subdomains obtained from various sources, for example:-

subfinder -silent -d hackerone.com | dnsx -silent

a.ns.hackerone.com
www.hackerone.com
api.hackerone.com
docs.hackerone.com
mta-sts.managed.hackerone.com
mta-sts.hackerone.com
resources.hackerone.com
b.ns.hackerone.com
mta-sts.forwarding.hackerone.com
events.hackerone.com
support.hackerone.com

dnsx can be used to print A records for the given list of subdomains, for example:-

subfinder -silent -d hackerone.com | dnsx -silent -a -resp

a.ns.hackerone.com [162.159.0.31]
b.ns.hackerone.com [162.159.1.31]
mta-sts.hackerone.com [185.199.108.153]
events.hackerone.com [208.100.11.134]
mta-sts.managed.hackerone.com [185.199.108.153]
resources.hackerone.com [52.60.160.16]
resources.hackerone.com [52.60.165.183]
www.hackerone.com [104.16.100.52]
support.hackerone.com [104.16.53.111]

dnsx can be used to extract A records for the given list of subdomains, for example:-

subfinder -silent -d hackerone.com | dnsx -silent -a -resp-only

104.16.99.52
104.16.100.52
162.159.1.31
104.16.99.52
104.16.100.52
185.199.110.153
185.199.111.153
185.199.108.153
185.199.109.153
104.16.99.52
104.16.100.52
104.16.51.111
104.16.53.111
185.199.108.153
185.199.111.153
185.199.110.153
185.199.111.153

dnsx can be used to extract CNAME records for the given list of subdomains, for example:-

subfinder -silent -d hackerone.com | dnsx -silent -cname -resp

support.hackerone.com [hackerone.zendesk.com]
resources.hackerone.com [read.uberflip.com]
mta-sts.hackerone.com [hacker0x01.github.io]
mta-sts.forwarding.hackerone.com [hacker0x01.github.io]
events.hackerone.com [whitelabel.bigmarker.com]

dnsx can be used to probe DNS Staus code on given list of subdomains, for example:-

subfinder -silent -d hackerone.com | dnsx -silent -rcode noerror,servfail,refused

ns.hackerone.com [NOERROR]
a.ns.hackerone.com [NOERROR]
b.ns.hackerone.com [NOERROR]
support.hackerone.com [NOERROR]
resources.hackerone.com [NOERROR]
mta-sts.hackerone.com [NOERROR]
www.hackerone.com [NOERROR]
mta-sts.forwarding.hackerone.com [NOERROR]
docs.hackerone.com [NOERROR]

dnsx can be used to extract subdomains from given network range using PTR query, for example:-

echo 173.0.84.0/24 | dnsx -silent -resp-only -ptr

cors.api.paypal.com
trinityadminauth.paypal.com
cld-edge-origin-api.paypal.com
appmanagement.paypal.com
svcs.paypal.com
trinitypie-serv.paypal.com
ppn.paypal.com
pointofsale-new.paypal.com
pointofsale.paypal.com
slc-a-origin-pointofsale.paypal.com
fpdbs.paypal.com

Wildcard filtering

A special feature of dnsx is its ability to handle multi-level DNS based wildcards and do it so with very less number of DNS requests. Sometimes all the subdomains will resolve which will lead to lots of garbage in the results. The way dnsx handles this is it will keep track of how many subdomains point to an IP and if the count of the Subdomains increase beyond a certain small threshold, it will check for wildcard on all the levels of the hosts for that IP iteratively.

dnsx -l airbnb-subs.txt -wd airbnb.com -o output.txt

📋 Notes

• As default, dnsx checks for A record.
• As default dnsx uses Google, Cloudflare, Quad9 resolver.
• Custom resolver list can be used using r flag.
• Domain name input is mandatory for wildcard elimination.
• DNS record flag can not be used when using wildcard filtering.

dnsx is made with 🖤 by the projectdiscovery team.