1. A computer may have multiple adapters and multiple IP addresses. We called these multi-homed hosts. The existence of such machines makes some security processes difficult. UDP based transactions (like DNS) sometimes show anomalies because the responses come back from IP addresses different than the one the request was sent to. Sun workstations demonstrate and even more difficult problem: if multiple adapters are installed within the workstation, they are all assigned the same MAC address. Sometimes people hook both adapters to the same ethernet network. This means that every incoming packet is received by both adapters, so every request is seen multiple times, and responded to multiple times. The symptoms are that on UDP based protocols, every request sent to the multi-homed Sun computer gets multiple responses back. Key point: Misconfigured multi-homed hosts are common enough that it makes distinguishing their anomalies vs. hacker anomalies difficult. From Hacking-Lexicon