Checking which DC is being used during user logon process

In environments with multiple sites / subnets and domain controllers you may be looking for such information really often. There are at least three options to determine which DC was used for authentication of client.

First two possibilities are almost the the same (they are based on the same environment variable). You can either type in and run “echo %logonserver%” or “set l”, but actually & unfortunatelly both of them are not really accurate because of update times for logonserver variable.

logonserver

Another option, which provides more accurate result is nltest with dsgetdc option.

nltest dsgetdc

nltest can be used for various checks – as in the example above, it provides big amount of data about domain authentication:

  • DC used during user authentication process,
  • AD Site you are in,
  • AD site that DC is in.

Not a big thing, but I hope you will find it useful.

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