Hello,\n\nWe have a Cisco 2901 with multiple WICs and three of the Routing Interfacesare connected to the same single dumb switch. \n\nObviously the interfaces should not normally be connecting to the same switch, but that's how our system is currently designed. \n\nThe odd thing is when a Windows PC (no IP yet) and another device (device A,for example IP 10.10.10.1) are both connected to this same dumb switch, when we try to configure an IP on the Windows PC, the PC responds with IP address conflict. We are sure there is no IP conflict, but the message comes up everytime.\n\nEven though we can try any random IP on the Windows PC, it always responds with IP conflict. \n\nIf I remove the three network cables from the router interfaces, with just the Windows PC and device A connected, I can configure the Windows PC IP with no problem and communicate with device A. Ever after putting the cables back into the router, everything seems fine at that point.\n\nSo the problem seems to only appear when trying to set an IP on the PC, butonce the IP is set, all seems well. I'm certain it's not related to a true IP conflict, but maybe something in the way Windows detects IP conflicts? \n\nMaybe PC having the same MAC address across multiple interfaces causes this????\n\nDoes anyone know why the PC would think there is an IP conflict when tryingto set the IP? \n\nVery curious...\n\nThanks in advance!