I am new to Windows world. Hence please do correct me if you find any terminology to be incorrect than the standard ones. I would be more than glad to stand corrected. I am learning about the LDAP and Active Directory servers. We all know that for logging into a domain, active directory (AD) service for that domain is used. But how does the windows running in your workstation find out which AD to be contacted? After we click on the login button, a name service look-up is performed with the following details: Request type: SRV URL: _ldap._tcp.domainname This NS look-up command will return a bunch of servers, and one of them will be used to authenticate the user. Each of the blocks in the response will have the port in which the server is listening as well. Replace domainname above with the actual domain name in which you would like to find out the active servers. Okay, thats the theory part. Now hands on. Try these commands in your workstation and convince yourself with the results...