# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 08:00:27:ae:37:c3 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.78/24 brd 192.168.0.255 scope global enp0s3
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:feae:37c3/64 scope link
       valid_lft forever preferred_lft forever
3: enp0s8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0 state UP qlen 1000
    link/ether 08:00:27:de:5c:44 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::bf94:3bfe:ab51:da40/64 scope link
       valid_lft forever preferred_lft forever
4: enp0s9: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0 state UP qlen 1000
    link/ether 08:00:27:9b:01:38 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::ca80:faec:c053:f8f0/64 scope link
       valid_lft forever preferred_lft forever
5: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether 8a:05:b6:56:51:9c brd ff:ff:ff:ff:ff:ff
6: dummy1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether f6:fa:9a:23:3c:90 brd ff:ff:ff:ff:ff:ff
13: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether 08:00:27:9b:01:38 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::a00:27ff:fe9b:138/64 scope link
       valid_lft forever preferred_lft forever


# brctl show br0
bridge name bridge id       STP enabled interfaces
br0     8000.0800279b0138   no      enp0s8
                                    enp0s9

# brctl showmacs br0
port no mac addr        is local?   ageing timer
1   08:00:27:01:4b:e0   no       141.71
2   08:00:27:9b:01:38   yes        0.00
2   08:00:27:9b:01:38   yes        0.00
1   08:00:27:de:5c:44   yes        0.00
1   08:00:27:de:5c:44   yes        0.00


# sysctl.conf
net.bridge.bridge-nf-call-arptables = 1
net.ipv4.conf.br0.arp_accept = 1
net.ipv4.conf.br0.arp_ignore = 0
net.ipv4.conf.br0.arp_announce = 0
net.ipv4.conf.br0.arp_filter = 0
net.ipv4.conf.br0.proxy_arp = 0
net.ipv4.conf.lo.arp_accept = 0
net.ipv4.conf.lo.arp_ignore = 0
net.ipv4.conf.lo.arp_announce = 0
net.ipv4.conf.lo.arp_filter = 0
net.ipv4.conf.lo.proxy_arp = 0
net.ipv4.conf.default.arp_accept = 0
net.ipv4.conf.default.arp_ignore = 0
net.ipv4.conf.default.arp_announce = 0
net.ipv4.conf.default.arp_filter = 0
net.ipv4.conf.default.proxy_arp = 0
net.ipv4.conf.all.arp_accept = 1
net.ipv4.conf.all.arp_ignore = 0
net.ipv4.conf.all.arp_announce = 1
net.ipv4.conf.all.arp_filter = 0
net.ipv4.conf.all.proxy_arp = 1