Hi Syam --
Tableau relies on the network stack & operating system it is installed on to access remote machines. Since Windows generally can't get into a Unix file system without extra "stuff" to help it, Tableau won't be able to either.
While I haven't tested this, I'd think that using Samba or some similar type of software to enable Windows to Unix file sharing would get you what you need.
Let us know what you end up doing!
if you had got the solution, please suggest me too. i am working on same