A proper company will be listed in Ministry of company affairs website.
http://www.mca.gov.in/DCAPortalWeb/dca/MyMCALogin.do?method=setDefaultProperty&mode=16
Go to the link and search for the company you wish to search. From this you will know when and where it was registered.
A good company would write its history in a neat format, from the humble beginning and achievements till date.
Check out the domain here also.
So next time when u go for any interview check all these…
Google search the address mentioned. Confirm the address and co name. And , then proceed as you wish.
Thanks to all the inputs from