Multiple physical network interfaces on the same subnet may cause routing issues
You should avoid configuring your server with more than one network interface on on a single subnet. Clients may have issues communicating with a server that is configured this way, and it may lead to other unexpected behavior.
To avoid this, do one of the following:
To use your server as a gateway between a private network and the Internet, configure one network interface for each separate network. For more information, see the Network Services Administration Guide available from Apple - Support - Manuals.
To increase available network bandwidth by combining two Ethernet ports, create a single bonded network interface. For more information, search Mac Help for "Combining Ethernet ports".
To use more than one IP address on the same subnet, assign them both to the same physical interface. For more information, search Mac Help for "Adding a network service".