This situation is applicable for users that have two or more Network Interface Cards (NICs) on a Windows PC. These NICs may be connected to the same network or to separate networks.

For example, NIC 1 might be on a private domain and NIC 2 on a public domain. Users want to use OPC DA to connect this multiple NIC PC to another application on a remote computer. This remote computer must be on the same network as one or both of the NICs. OPC DA uses Microsoft's Distributed Component Object Model (DCOM) to make this connection.

• If both NICs are on the same network, DCOM will look for the remote PC node using all NICs on that network (in Windows 2000 and higher). The OPC DA connection would be made through the NIC that was first in the network bind order, or the first NIC that successfully connected to the remote PC.
• If the two NICs point to separate, non-overlapping networks, the connection will be made via the NIC on that network. For example, if the remote PC is on the private domain, the OPC DA connection would be made using the NIC on the private domain.