I have a weard behavior in a small LAN where some PCs "wired" cannot get connected to the network nor get an IP address from DHCP. to be specific, the network has: 1. Win 7 clients, NICs have auto negotiate on, Jumbo packets off 2. Dlink unmanaged switch 10/100, 24-ports, all are auto negotiate, auto sense 3. ISP router with DHCP service that's working fine Problem: some PCs with NVIDIA nForce NICs gets the "Unidentified network" when plugged to the Dlink switch. trying to remove the NIC and restart does not fix the problem, tring ipconfig/release doesn't fix it as well, and trying to assign them a static IP also doen't fix it. Had to use another Netgear unmanaged switch "also all its 16 ports are auto negotiate and auto sense", attached it to the router and connected it to the Dlink "downlink" so now Dlink is connected to the ISP router through the Netgear switch. so now the network now as follows: some PCs connect to Dlink which has traffic to the router through the Netgear switch and other PCs are directly connected to the Netgear which goes to the internet through the router. To this point, all are happy but my problem is why can't I simply move all PCs to my Dlink 24 ports and remove the netgear "16-ports" from the network, use it in somewhere else.