This is a 64-bit counter, accumulated since the last reboot, of connection attempts for the specific protocol denoted by cufwConnProtocol that were declined because of resource unavailability. An admin uses this to see whether resource exhaustion is concentrated on one particular protocol's connections rather than firewall-wide. For example, a high value here for one protocol while others remain low would suggest that protocol's traffic pattern, perhaps many short-lived connections, is disproportionately consuming the firewall's connection resources.