Thanks Nikher for the quick reply.
That is one way of knowing it, which we are currently aware of.
I am primarily looking for an approach from server admin point of view.
We have hundreds of workbooks and only a small fraction of them have those external connections. Naturally we don't want to open every workbook to know whether or not there is an external connection.
We want to know if there is an easy way to identify those with an external connection.