Is Chidambaram a shetty ?

I never get this thing exactly right. I know many Chidambarams who are highly educated, but it seems they are Chettiars, or something like Shetty from the town Chidambaram in Chettinad, Tamil Nadu. Did I get that right ? Gosh, this thing really puts me off. How do you identify someone's caste, without actually asking a native. Here are some places a foreign student or NRI could make blunders. Shashi Tharoor sounds similar to Shashi Kapoor. Only after his marriage to this enigmatic "businesswoman" Sunanda Pushkar, did I note that he is a Malayalee Nair, not a punjabi born in Kerala. Mira Nair aint not a nair but actually Mira Nayyar, a hardcore Punjabi. Ambani and Malani could be related to Balani but it turns out they are usually gujarati speakers from the Kutch in neighboring Saurashtra. Sachdeva sounds like a south Indian but is usually Sindhi from south. Maniar sounds like Nambiar but is not a south indian; is gujarati. Yes! Chittal sounds like Mittal, but is not an agraseni. The great musician Milind Chittal posted a note informing me he was something like "Chittar", a GSB from Karwar. I have made certain huge errors trying to come up with formulas to identify castes in India, for whatever it was worth; this effort promptly abandoned. It goes out of rhyme pretty often.