|But, if I turn off 1st DC in 1st site, clients cannot login to domain in this site, |
This is to be expected since the clients at that site will authenticate to that DC. This is why it's recommended you create a second, redundant DC in every location. That way if the one dies, users can still login to the domain and work.
but 2nd DC in 2nd site is working properly. Why clients cannot login to 2nd DC? All servers are Win 2003 R2 32bit
Well, mainly because it's not a redundant DC. Also, it's because it's in a different physical location and a separate logical site within AD.
I don't know that you could make it redundant and have users in site A authenticate to the DC in site B. If there is a way to do this, hopefully someone else who knows how will respond and explain how. But I suspect you can't and will have to bring up a second DC in site A and make it redundant.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.