Techniques described herein enable peers to determine each peer's NAT type much more efficiently and quickly than when compared with existing techniques. To do so, a peer simultaneously sends multiple test messages to a server. The peer then waits to either receive a response for each of the multiple test messages or may store an indication that no response has been received after a predetermined timeout period. The peer then analyzes the received responses and/or the stored timeout indications to determine the peer's NAT type or to determine that the peer is operating free from concealment by a NAT/firewall device. By simultaneously sending the multiple test messages, the peer may determine the NAT type within a maximum time defined by the predetermined timeout period or a roundtrip time period that is required for communication between the peer and the server. As such, the tools allow for efficient NAT-type detection.