Finding all sub domains of a main domain

Problem: Need to know all the sub domains of a main domain, e.g. example.com has a sub domain dev.example.com , I also want to know other sub domains.

Solution:

Install the package called sublist3r, written by Ahmed Aboul-Ela

$ sudo apt install sublist3r

run the command

$ sublist3r -d example.com -o subdomains-example.com.txt

                 ____        _     _ _     _   _____
                / ___| _   _| |__ | (_)___| |_|___ / _ __
                \___ \| | | | '_ \| | / __| __| |_ \| '__|
                 ___) | |_| | |_) | | \__ \ |_ ___) | |
                |____/ \__,_|_.__/|_|_|___/\__|____/|_|

                # Coded By Ahmed Aboul-Ela - @aboul3la

[-] Enumerating subdomains now for example.com
[-] Searching now in Baidu..
[-] Searching now in Yahoo..
[-] Searching now in Google..
[-] Searching now in Bing..
[-] Searching now in Ask..
[-] Searching now in Netcraft..
[-] Searching now in DNSdumpster..
[-] Searching now in Virustotal..
[-] Searching now in ThreatCrowd..
[-] Searching now in SSL Certificates..
[-] Searching now in PassiveDNS..
Process DNSdumpster-8:
Traceback (most recent call last):
  File "/usr/lib/python3.12/multiprocessing/process.py", line 314, in _bootstrap
    self.run()
  File "/usr/lib/python3/dist-packages/sublist3r.py", line 269, in run
    domain_list = self.enumerate()
                  ^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/sublist3r.py", line 649, in enumerate
    token = self.get_csrftoken(resp)
            ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/sublist3r.py", line 644, in get_csrftoken
    token = csrf_regex.findall(resp)[0]
            ~~~~~~~~~~~~~~~~~~~~~~~~^^^
IndexError: list index out of range
[!] Error: Google probably now is blocking our requests
[~] Finished now the Google Enumeration ...
[!] Error: Virustotal probably now is blocking our requests
[-] Saving results to file: subdomains-example.com.txt
[-] Total Unique Subdomains Found: 7
AS207960 Test Intermediate - example.com
www.example.com
dev.example.com
m.example.com
products.example.com
support.example.com
m.testexample.com

We can see the subdomains listed at the end of the command output.

enjoy, have fun, drink water!