An electronic device includes multiple networking devices arranged in a stack. The networking devices may include configurable ports, where a given configurable port in the configurable ports may be configured as a data port or a stacking port. During operation, a networking device in the stack may be designated as a master in the stack. In response, the networking device may provide one or more probe messages to determine a state of the networking devices, where the state includes one or more connections among the networking devices. Then, the networking device may verify that the one or more connections are correct. When the one or more connections are correct, the networking device may define a subset of the configurable ports in the networking devices as stacking ports.