I used the DHCP utility on my firewall to determine that a .35 and .105 are downloading a lot, maybe a virus or maybe yahoo launch or something. I would like to find those computers in our network, but unfortunately when I do a DNS lookup on our DNS server those addresses are not listed. .100 and higher is for DHCP, while under .99 is static (so that should be easier to find, right?). Is there a way to block specific IP addresses from doing anything, or way to locate them or what they are doing? (tools, etc).