Question : How do I force pc's in one site  to hit a specific domain controller

How do I force pc's on onr site to hit a specific domain controller for authenticaiton or search purpose..
how can I make the dns server resolve the name of the domain with the same ip address event though I have sevral domain controlers  than can respond to the same name of the domain with different ip address.

Answer : How do I force pc's in one site  to hit a specific domain controller

[1] If the DCs are in different physical locations, configure the appropriate Site and Subnet information in the AD Sites & Services MMC snap-in.

[2] If you have multiple DCs in a single physical site, modify the weight/priority of the SRV records of the DCs within the site: http://technet2.microsoft.com/WindowsServer/en/Library/70919369-262d-491d-89d9-c45d7654b32c1033.mspx