I have a USB-to-ETHERNET adapter (CP-USB-RJ45M) with which I am trying to create an ethernet bridge in CentOS Linux for ip-forwarding within a private LAN test network. I modified my /etc/rc.local file to create the bridge upon startup as follows:
/sbin/ifconfig eth0 0.0.0.0 up /sbin/ifconfig eth2 0.0.0.0 up /usr/sbin/brctl addbr link3_br /usr/sbin/brctl addif eth0 /usr/sbin/brctl addif eth2 /sbin/ifconfig link3_br up
However, the USB-to-ETHERNET interface (eth2) will not enable. I have no IP address assigned to it, while eth1 has a statically defined IP and mask. Am I doing something wrong? I need to figure out how to get the bridge up and running so that ip-forwarding can occur. Please let me know if more details are required and I'll add to my question.
Edit: My original setup consisted of a server with 2 NICs where the ethernet interfaces have been successfully bridged. Each of those 2 ethernet connections goes to a different router. I am now trying to move those ethernet connections to a laptop where I connect one cable to the built-in ethernet port and the other one to my USB-to-ETHERNET adapter. In Wireshark, I can see OSPF DBDESC packets with the original server which works properly. When I connect the cables to my laptop, I only see OSPF hello messages.