I have used tcpdump to see what happens on my network and then i found this: 15:03:35.533019 10.1.3.19.netbios-ns > 10.1.2.1.netbios-ns: NBT UDP PACKET(137): QUERY; REQUEST; UNICAST 15:03:35.613019 10.1.2.1.netbios-ns > 10.1.3.19.netbios-ns: NBT UDP PACKET(137): QUERY; NEGATIVE; RESPONSE; UNICAST (DF) thats not good is it?