An improved technique is provided for compressing a packet classifier for a computer network system. A set of packet classification rules is first partitioned into one or more partitions. For each partition, columns of bits in each of the ternary strings of a given partition are reordered, the ternary strings within each partition are consolidated into one or more replacement strings and then the columns of bits of the replacement strings are rearranged back to the starting order. The rearranged replacement strings from each of the partitions are appended together to form a compressed packet classifier which may be instantiated in a content-addressable memory device.