Counts packets explicitly rejected outbound on the specific interface in this row. This would rise if the gateway itself is generating rejection responses out through a particular interface, worth checking that the interface sending the most rejects out matches the interface that's actually receiving the most probing traffic in, since a mismatch could point at asymmetric routing. Example: fwRejectPcktsOut rising on an internal interface while fwRejectPcktsIn rises on the external one is consistent with reject responses being routed back out a different path than the request came in on.