2 Domains on the same IP range 1

[wbow]

I have been tasked to co-locate 2 businesses, Adomain and Bdomain which are currently in 2 separate offices with no connection, but use the same private IP range of 10.x.x.x on a subnet mask of 255.255.255.0.
The primary business [Adomain] has just been transformed from Windows 2003 Small Business Server to a full Windows 2003 enterprise server environment and has a Linux Server as a firewall. The secondary business [Bdomain] still uses a mix of Windows 2003 Small Business Server and Windows 2000 Server.
I must ensure that each group of users [all Windows XP Pro machines and one or two Vista] are able to login to their existing servers and profiles, and additionally have network drive mappings to the other domains servers and file shares.
The current thinking is to co-locate the servers, using common switches and routers and demote the Windows 2003 SBS machines to member servers.
Does anyone have experience of a co-location such as described above or has anyone advice/options to offer.

 

[ShackDaddy]

Probably the best thing you could do is make sure that one of the businesses uses only static IP addresses. Your main danger is that clients will get IP addresses from the other business's server and will then be unable to connect to their own, due to DNS issues.

If you static IP'd the whole office and configured each client to use its own server for DNS, you shouldn't have any issues. If you use DHCP in your network, then one organization should be completely static. I don't think I need to tell you that you shouldn't have two DHCP servers on that network. It's possible to pull off, but it takes some specialized configuration, and if you don't have that many workstations, it is probably easier to just static IP the workstations.

If you want clients to be able to map drives to the other server, then you should probably configure both domains with a WINS server and then configure those servers to replicate with each other. Once you've done that, clients in one domain should be able to map drives to shares on the other domain's server IF (pay attention) they have credentials from the target domain to provide. Because you are using SBS, you can't create a trust between the domains, so that means that User A in Domain X will need credentials (a user account & password) in Domain Y in order to access a file share there. You may find that you can just allow anonymous access to the share, but that can be a security liability.

Lastly, you can't demote an SBS server. You can only reinstall it using standard Windows 2003 server media.

Dave Shackelford
Shackelford Consulting