Selectively using network address translated mapped addresses based on their prior network reachability

Abstract

In one embodiment, network address translated (NAT) mapped addresses are selectively used based on their prior network reachability. One embodiment maintains for each particular mapped address (e.g., NAT public address pool member), a reachability status level based on prior usage of the particular mapped address to communicate with external destinations. By continuously monitoring the reachability 'health' of mapped addresses, problem-experiencing mapped addresses can be avoided. One embodiment monitors the success and/or failure rates of connection attempts over a rolling time period to provide an up-to-date current view of the reachability status level of corresponding mapped addresses. In one embodiment, a network address translation device assigns, based on their reachability status level, these mapped addresses. One embodiment provides an administrative notification for particular mapped address or ceases using the particular mapped address in response to its reachability status level falling outside a predetermined or calculated level.