Which DNS?

I would like to know which DNS server (primary or secondary) Windows uses at any given time.
My OS is Windows 7 Ultimate 32-bit.
Can anyone help me with that please?

 

Any OS, whether Windows or Linux, tries to use Primary DNS first. If it fails, it goes to Secondary & Tertiary and so on.

 

Yes, I know.
But if for some reason (e.g. the primary server becomes unavailable) it switches to the secondary server, but it never switches back (even if the primary sever becomes available again or the secondary server must be unavailabe as well then it switches back).
My question is: can I know which DNS server the OS uses at any given time?

 

Never ever thought about it to be honest. If it works, I don't care what DNS server its using.

 

Well, you should if you have a local DNS server installed (with local DNS entries, known to the intranet but not known to the Internet).