# What Do I Do If the Communication Between the Primary NIC and Extension NIC of the BMS is Abnormal?

#### Cause

If two NICs on the same network segment are added to a BMS, communication between the primary NIC and extension NIC is abnormal because the BMS gateway strictly verifies the source MAC addresses. For example, in Figure 1, the primary NIC and extension NIC are both on the 172.22.9.X network segment. A policy-based route needs to be configured to enable communication between the NICs.

Figure 1 Network segment of the NICs

#### Solution

1. Run the following command to add two routing table names (net1 and net2) and priorities (252 and 251) to the /etc/iproute2/rt_tables file:

   vi /etc/iproute2/rt_tables

       252     net1
       251     net2

2. Run the following command to add the NIC routing information to the /etc/rc.local file:

   vi /etc/rc.local

   For example, the IP address of the primary NIC is 172.22.9.7, that of the extension NIC is 172.22.9.206, and that of the BMS gateway is 172.22.9.1, add the following routes:

       ip route add 172.22.9.0/24 dev bond0 src 172.22.9.7 table net1
       ip route add default via 172.22.9.1 dev bond0 table net1
       ip route add 172.22.9.0/24 dev bond0.3935 src 172.22.9.206 table net2
       ip route add default via 172.22.9.1 dev bond0.3935 table net2
       ip rule add from 172.22.9.7/32 table net1
       ip rule add from 172.22.9.206/32 table net2

Parent topic: Network and Security FAQ