This counts packets that were discarded specifically because a QoS rule had its 'Filter' flag set, meaning the rule was configured to block matching traffic outright rather than shape or deprioritize it. On this satellite/WAN modem, admins use this counter to confirm a filter-mode QoS rule is actually intercepting the traffic it targets, since a value stuck at zero would mean the filter's match criteria never actually catch real traffic. For example, a rule set to filter a noisy broadcast protocol showing this counter climb from 0 to 15,000 over an hour confirms the filter is actively blocking that traffic.