How to set up a 2nd network card?

Question

CentOS

Good. I've been fighting for a long time, it doesn't work. The essence of the problem is this. Installed FreePBX distro on the server. The server has 2 network cards. During installation, I assigned them IP addresses manually as static (for eth0 192.168.1.10/24 , for eth1 192.168.200.20/24 for example). After that, the following picture turned out: the eth0 network software traffic goes in both directions perfectly, the server can communicate with the world over the eth1 network, but incoming requests do not go through, but in iptraf-ng, when choosing eth1, you can see that my computer is knocking on it, but in response silence. What could be the problem?
For the sake of interest, I tried to disable the firewall on both cards in FreePBX, the result is 0

Answer 1

The problem was solved in the following way. We swapped the subnets on the network cards, disabled one of the subnets (which in the situation was eth0, moved it to eth1) and configured routing to that subnet at the router level. With the 1st card, everything works. Balancing normal did not work, while left so.

Answer 2

Check on Centos the routes that you had to register for subnets, the files start with route-enp*
In this file you force the subnet and interface through which they should communicate.