How to find all hidden sub domain name of a website | Domain name

hello every one this is a small post where i will discuss finding sub domain name of a target website.
So what exactly subdomain name ..its basically a name that s attached to beginning of a domain name like.

abc.xyz.com
xxx.xyz.com
123-xs.xyz.com

Domain name owner usually create such subdomain name in order to create one more side of there Business requirements.
so as we know some domain name are publicly available but there also some priv8 /hidden domain name that also exist which the owner of domain name might use for internal purpose.

so how we can find those hidden sub domain name so here are some ways by which you can easily find the sub domain name of a website.

Using google

you can simply use a simple google search like.

*.xyz.com

which will list all possible subdomain name indexed by google.com.

Demo.

*.darksite.co.in

Using Online site

There are various website which are available for finding possible domain of a website but one of them is .

Wolframalpha

it just list you all possible domain using their DNS analysis.

So is it important to find subdomain name of a website for hackers ?

The answer is very simple .sub domain name usually helps hackers to find the vulnerable url and exploit it. few months back one pakistani guy Rafay Baloch got 5,000$ for finding a sub domain name of paypal and he just guessed the password to be "root".so do find some hidden sub domain and all the best :) .