I have setup a secondary domain controller with server 2000 and would like to find out ways to confirm the functionality.I don't have ant error in the log but is there a way to understand if it is working beside unplugging the Ethernet cable from primary?
You will have to monitor the DC long enough to determine if it’s being used or not. Here are a couple tools I suggest.
Use NetMon or Wireshark to capture network traffic. You can capture all inbound LDAP queries on a specific DC and build a list of source addresses.
You could try using AD Insight http://technet.microsoft.com/en-us/sysinternals/bb897539