How to switch 2 ADs

All this comes down to Sites.. and GC placement.. you should have a GC in each site.

The KCC determines the users closest Domain Controller for intra-site replication.. When you define another site in AD you create a Site Link to control Replication... How have you defined your Sites in AD?

Some more reading: http://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/activedirectory/stepbystep/adsrv.mspx

Your description is a bit confusing - I assume that this is the same domain on two sites with at least one DC in each site.

If that is the case then you need to make sure that at least one machine on each site is a Global Catalog Server - to check and/or set, go to Administrative Tools, Active Directory Sites and Services, Expand, Sites, Default first site and Servers. Right click on the new server and select properties and tick the"Global Catalog" checkbox. (Global catalog is essential for logon as it needs to be queried to establish Universal Group Membership)

You also need to make sure that a machine on each site is a DNS server. You can install DNS if necessary using the "configure my server wizard" or you can use You can do this through Add/Remove Programs->Windows Components->Networking Services->DHCP.

Assuming that you are using Active Directory Integrated DNS on the first Domain Controller, DNS will automatically replicate to the new domain controller along with Active Directory. Set up forwarders as detailed at http://www.petri.co.il/configure_dns_forwarding.htm to allow external resolution

You then need to configure all the machines on each site to use the DC on their own site as the preferred DNS server, and the DC on the other site as their alternate DNS server.

Both Domain Controllers by this point will have Active Directory, Global Catalog, DNS and the domain could function for a while at least should any one of them fail.

If you are using DHCP you may also want to put a DHCP server on each site, with non-overlapping scopes.

These two server are connecting via Fiber Optic.
IP address is 10.10.10.10, 10.10.11.10. All users taking IP addres from firewall. These 2 servers Domain Controller, and DNS servers.

If the Active Directory Domain contains 2 DCs in Different Sites, and Active Directory Sites and Services is configured correctly with Subnet Information, then if 1 DC goes down at location1 the computers @ location1 will automatically connect to a DC in location2 if they have network access to it.
Here is how XP finds a DC to connect to: http://support.microsoft.com/kb/314861

If you are still having a problem with this, here is a link on how to force workstations to use a specific DC.  http://windowsitpro.com/article/articleid/13535/how-can-i-force-a-client-to-validate-its-logon-against-a-specific-domain-controller.html

Note: If the DC that is running FMSO roles becomes unavailable new objects will not be able to be created in AD until it is back online.

Hope this points you in the right direction.

With the setup you describe there should be no issues - just follow the instructions I gave earlier. If you have defined the subnets in AD Sites and Services and associated them with a site then clients will first attempt to authenticate with the DC in their own site and only use the other if there is a problem. However you still need to provide DNS and GC on both sites and configure the clients to use the local DNS server in preference.

OK i will Test it today and i will tell you guys.

Problem was DNS settings.
AD1 and AD2 is DNS servers.
For Network Bridge Configuration: for both connections:
TCP/IP properties->General Tab:

Location1
Preferred DNS server AD1 DNS
Alternate DNS server AD2 DNS
Location2
Preferred DNS server AD2 DNS
Alternate DNS server AD1 DNS

Thanks you guys helping for special thanks for NoEvil.