Windows Server 2008 Domain Controllers fail to communicate on different subnet

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  • Hi,

    I need some help in figuring out how to make two DC's communicate with each other which are on two different subnet. Here's how my network in VM Workstation is setup and what i'm trying to do exactly:

    I got 4 DC (all server 2008 R2), all 4 on a subnet 172.16.5 statically assigned IP's from to in a Bridged mode. My machine has 2 physical NIC Card connected to the Router via cable. Only one physical NIC is being used and that also provides the internet. The Router has a DHCP setup and the Ip of the router is The problem i'm facing is that i'm trying to create a new Domain named signal.local and it'll be on different subnet, let's say 192.168.4 and in order to create an external trust between new domain and other 4 DC's with different subnet, they have to communicate with each other first which is not happening. My first 4 DC are GC as well as DNS servers and this new domain is going to be a GC and DNS as well. 

    I'm actually self studying for Active Directory Server 2008 (70-640) by watching videos and practically testing it out on the VM Workstation. According to the video, it says that In order for the communication to take place between DC's on different subnet, a VPN tunnel must be created between two subnets. I googled it and came across lof of different advices like, create host record in DNS, or setup conditional forwarding, add domain names or IP under Server Name tabs in DNS, or create Stub Zone, Primary Zone, or secondary zones and i tried that all one by one but they all failed. 

    I even saw an article where someone suggested to setup RRAS on the server for routing the IPs of the two subnet. I'm confused by all the advicces or the articles i saw online and i'm stuck with it. Can someone please help me out with the right advice as to how i can resolve this problem.

    Another thing i want to know is, let's say if i have to setup VPN or RRAS or both then i want to know is if i'll have to create a new virtual machine with Server 2008 R2 and setup either VPN or RRAS on it or i can setup VPN or RRAS on one of the existing DCs. It's driving me nuts with all the time i've spent so far.

    Please share the correct instructions for VPN and RRAS if that's what i'll require in the end to have on both the servers or just one server. Also, let me know how many VNIC inside vmware i'll need on the server and what mode they should be in like Bridge, NAT or Host-only. Please share the solution in details.




    Thursday, January 05, 2012 6:30 AM

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