How to set up a second network interface in centos?

Question

CentOS

there is ip 100.233.433.137 which leads to the virtual machine 20.0.0.439 (only the ssh port is forwarded by port forwarding) there is a poppy interface address. a second network card is connected, which is not registered in the system. you need to connect it and register the ip settings, mask, gateway, dns. ifconfig is missing, I set up ip link (set, etc.) and it worked only on the local network.
it should turn out that the main ip will not be tied to the local network, and will be a completely separate external address.

Can you tell me how to do this as a newbie?

Answer 1

Che is somehow difficult ...
We look at the network card:
lspci | grep ethernet

03:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev 12)
0b:00.0 Ethernet controller: Intel Corporation 82571EB Gigabit Ethernet Controller (Copper) (rev 06)
0b:00.1 Ethernet controller: Intel Corporation 82571EB Gigabit Ethernet Controller (Copper) (rev 06)
0c:00.0 Ethernet controller: Intel Corporation 82571EB Gigabit Ethernet Controller (Copper) (rev 06)
0c:00.1 Ethernet controller: Intel Corporation 82571EB Gigabit Ethernet Controller (Copper) (rev 06)

As far as I remember, centos stores map settings here:
cd /etc/sysconfig/network-scripts/
then
vi ifcfg-eth0 or whatever interface you have and configure the map