1. A system, including: a processor; and a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to: set an option in a first ICMP query to a first state; set the option in a second ICMP query to a second state, wherein the first state of the option and the second state of the option are different; send the first and the second ICMP queries to the target computer; receive responses associated with the first and second ICMP queries from the target computer; and determine an attribute of the target computer comprising an indication of the behavior of the target computer with respect to the option at least in part by matching the received responses to a behavior classification in a set of candidate behavior classifications.