Fast lookup filters (FLT)

The fast-lookup-filter option is available at the [edit firewall family (inet | inet6) filter filter-name] hierarchy level. Fast lookup filters can boost filtering performance by as much as three to four times for filters under 3000 terms. Within the firewall filters and their terms, ranges, prefix lists, and the except keyword are all supported. 

Note: New match conditions for fast lookup filters were introduced for PTX Series in 25.2R1. See linked documentation for details.