How can I reliably tell which NIC is the main one in a multi NIC machine such as windows or Linux.
For example, say a Windows and a Linux box have 4 NICs each.
One or more NICs may or may not have IPs configured.
One or all could be private IP or a combination of public and private.
Some might be virtual IPs on one NIC.
Is there some way of knowing which is the main NIC? For example, we'll often configure a machine which has more than one NIC with the first NIC being the 'main' one if you will, the one which will carry most of the traffic.
Is there some way of knowing which NIC is transferring the bulk of the traffic without checking packet counts?