In one embodiment, a stateful device receives a packet on a particular interface of a stateful device in a computer network, where the packet includes source identification and destination identification. The source identification and destination identification of the packet may then be swapped and checked against a stateful connection table managed at the stateful device for the particular interface, such that a loop may be detected at the particular interface in response to the swapped source identification and destination identification matching an existing entry in the stateful connection table. In the event there is such a detected loop, the packet (e.g., and any subsequent similar packets) may to be dropped, accordingly.