Non-working bonding config in /etc/network/interfaces: auto enp4s0f0 iface enp4s0f0 inet manual
auto enp4s0f1 iface enp4s0f1 inet manual auto bond1 iface bond1 inet static address 192.168.12.4/24 gateway 192.168.12.1 slaves enp4s0f0 enp4s0f1 bond-mode 802.3ad bond-miimon 100 bond-downdelay 200 bond-updelay 200 (also mentioned in https://wiki.debian.org/Bonding) Working config: auto enp4s0f0 iface enp4s0f0 inet manual bond-master bond1 auto enp4s0f1 iface enp4s0f1 inet manual bond-master bond1 auto bond1 iface bond1 inet static address 192.168.12.4/24 gateway 192.168.12.1 bond-slaves none bond-mode 802.3ad bond-miimon 100 bond-downdelay 200 bond-updelay 200
