In general, techniques are described for encoding port ranges. In one example, a method includes generating an encoded value that represents a specified port range including a first element storing an identifier that identifies a frequently occurring port range stored in an associative data structure of most frequently occurring port ranges, a second element storing an index that represents a dynamically-learned port range specifying at least a part of the specified port range, the dynamically-learned port range represented in a tree-structure of dynamically-learned port ranges and identified by the index, and applying, by a forwarding plane of the computing device, one or more filters associated with the encoded value to a packet that specifies a port included in the specified port range.