Bridge

Install tools

Depending on your OS, install:

 sudo apt install bridge-utils
 sudo zypper install bridge-utils

Edit config

Depending on your OS, call:

 sudo vi /etc/sysconfig/network-scripts/ifcfg-br0
 sudo vi /etc/sysconfig/network/ifcfg-br0

Contents should look like

 DEVICE=br0
 TYPE=Bridge
 IPADDR='192.168.178.11/24'
 BOOTPROTO='static'
 ONBOOT=yes
 STARTMODE='auto'
 ZONE=public
 BRIDGE='yes'
 BRIDGE_PORTS='eth0'
 BRIDGE_STP='off'
 BRIDGE_FORWARDDELAY='15'
 GATEWAY=192.168.178.1
 NETMASK=255.255.255.0

Note that this is a bridge, not a router. So the IP addresses of one side of the bridge must be in the same subnet as on the other side.

Reboot the network

 systemctl restart network

Check your network

 ip link show
 ip address show