Multiple implementations of the DNS protocol, including (1) Poslib 1.0.2-1 and earlier as used by Posadis, (2) Axis Network products before firmware 3.13, and (3) Men & Mice Suite 2.2x before 2.2.3 and 3.5.x before 3.5.2, allow remote attackers to cause a denial of service (CPU and network bandwidth consumption) by triggering a communications loop via (a) DNS query packets with localhost as a spoofed source address, or (b) a response packet that triggers a response packet.