Hi, Was curious if someone could help out on this issue. Workstation has dual NIC's, one embedded, one PCI. Both are on seperate subnets. Machine is Windows XP Professional. The PCI NIC, Intel Pro 1000 MT Server Adapter, receives UDP multicast traffic at about 4Mb/s, .5% utilization of adapter, with the machine maxing out at 50% CPU utilization. Once this traffic starts coming the other NIC stops working. I can ping, tracert, to all resources, but can't connect to them on their port. For example: tracing to google.com works, but I can't connect to the website, telnetting on port 80 does not work. This is for external and internal resources. outlook etc etc. Only one gateway is configured and that is on the NIC that points to production/internet. When the traffic is stopped, the other connection starts working. This is duplicated on other machines. Any ideas? Thanks, J