Tool to capture all devices in Network /Domain

Techs,

In a large IT Infrastructure , i have 1000+ servers spread across different subnets & different Win2k & win2k3 & NT Domains. there are about more than 1800 servers approx.

Now i need to capture the hostnames & servers details of all the servers/devices in a network given a subnet or Domain. you can say this is to capture the server baseline.

I’d appreciate if any tech out there help me in finding a good tool which can provide me the above task. as end result with this tool i should be able to capture all servers in a given domain or subnet.