Bengie writes "From what I know about networks, you can't find out the MAC of an IP across a router. At some point I stumbled across a program that does just this. The only google hits I get talk about Netbios. Being able to do this would help out IT dept because our back-up registration page pulls MAC info from our DHCP server, but the DHCP database only syncs with our back-up database every 24 hours. If we build a new computer to replace an old one, our registration page can't get the new MAC for the Wake-on-LAN info until 24 hours later. We could use netbios if we had to, but that's kind of shady and won't work for our Mac computers since they don't have netbios. Is there a way of resolving the MAC of an IP across routers?"