A technique manages targets to which probe packets are sent from a source of a computer network. The novel target management technique dynamically selects an optimal set of valid targets for a particular (monitored) prefix of the computer network. Specifically, one or more targets are selected from a pool of possible learned and configured targets to be used as representatives of the monitored prefix. Probe packets are sent from the source to the selected targets for the duration of an evaluation period. Targets that do not respond to the probe packets during the evaluation period are invalid and deselected, and if available, an unused target is selected from the pool of possible targets to replace each non-responding target for a next evaluation period. Invalid learned targets are discarded, while invalid configured targets are returned to the pool of possible targets for potential re-selection in a later evaluation period.