NMCLI

Policy Based Routing

Return traffic on interface it came in on

The key is to add routes to the interface for a dedicated table. In this example I use table 2, add the two routes needed in place of 0.0.0.0/0.

set ipv4.routes 0.0.0.0/1 <gateway> table=2
set ipv4.routes 128.0.0.0/1 <gateway> table=2
set ipv4.routing-rules priority 100 to <int IP>/<prefix dev eth3 table 2
set ipv4.routing-rules priority 101 iif eth3 table 2
set ipv4.routing-rules priority 103 from <int IP> table 2

Create Bridge Interface

[root@natasha ~]# nmcli con add type bridge ifname br0
[root@natasha ~]# nmcli con add type bridge-slave ifname eno1 master br0
[root@natasha ~]# nmcli con edit bridge-br0
nmcli> set ipv4.addresses 192.168.11.120/24
nmcli> set ipv4.gateway 192.168.11.1
nmcli> save
nmcli> quit
[root@natasha ~]# nmcli con up br0