Manually connect elements in Diagram elements
You can use the Connection Tool to connect elements in diagrams manually.
If the connection you create has a red, crossed-out circle on it, the connection is not valid. A connection might be invalid, for example, if you connect an element to a network with an address range that does not include that element’s IP address. Such connections are allowed so that you can plan a configuration change without actually editing the elements until you are finished.
For more details about the product and how to configure features, click Help or press F1.