with dual-homed NIC's, we're experiencing a problem when certain programs are ran. The program is supposed to braodcast UDP packets on only one NIC, but for some reason it's broadcasting on both. This is causing a problem with our network, giving us more traffic. Does anyone know if there's a way to braodcast across only one NIC instead of both? please reply.

What are the IP addresses and netmasks of the 2 NIC's? Are you sure it's broadcast and not multicast packets? What is "the program"? Are your systems connected to a hub or a switch (preferably managed)?

the systems are connected via a switch in our server room. the program we are using is a java based program that our software programers are working on. and yes, it's a UDP broadcast. and to be a little clearer, one NIC is connected to our company network, the other connect amongst other compters around the office on their own little network (not connected to the internet at all). Also, we're experiencing some computers that are connected ONLY to the network WITHOUT internet access (only with one NIC in the system) and for some reason can still access the internet. please reply.

The advanced settings on the xp network ip can be used to block any udp,ip or protocol. Your question and later post are much different. You have a layer 2 issue or a gateway issue. By default xp can't relay or proxy data across two nic's. If all workgroup systems can access the net then you'd better see who set up a proxy or moved/added devices/wires.

Sounds like you have the dual homed nics bridged which would explain the internet access to those on the internal network. Sounds more like your programming is doing multicast not broadcast. Now if truely broadcast, since its to a lan, it may be the bridging is making it look like one lan which would result is both card transmitting the broadcast. Give a person a fish, they eat for a day. Suggest they internet search and they learn a skill for a lifetime.