/interface bridge
add admin-mac=xxxxxxxxxxx auto-mac=no comment=defconf name=bridge \
    vlan-filtering=yes

/interface vlan
add interface=bridge name=vlan100 vlan-id=100

/interface list
add name=WAN
add name=LAN

/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik

/ip pool
add name=vlan100_pool ranges=10.20.20.1-10.20.20.253

/ip dhcp-server
add address-pool=vlan100_pool bootp-support=none disabled=no interface=vlan100 \
    lease-time=1d name=vlan100_dhcp
add bridge=bridge comment=defconf interface=ether12 pvid=100

/interface bridge vlan
add bridge=bridge vlan-ids=1
add bridge=bridge tagged=sfp-sfpplus1,bridge vlan-ids=100

/ip address
add address=192.168.88.1/24 comment=defconf interface=bridge network=\
    192.168.88.0
add address=10.10.0.9/24 interface=ether2 network=10.10.0.0
add address=10.20.20.254/24 interface=vlan100 network=10.20.20.0

/ip dhcp-server network
add address=10.20.20.0/24 dns-server=8.8.8.8,8.8.4.4 gateway=10.20.20.254 \
    netmask=24

/ip firewall nat
add action=masquerade chain=srcnat out-interface=bridge src-address=\
    10.20.20.0/24

/interface bridge port
add bridge=bridge interface=ether12
/interface bridge vlan
add bridge=bridge tagged=ether12 vlan-ids=100
/ip address
add address=10.10.0.9/24 interface=ether12 network=10.10.0.0
;

[admin@RouterOS] /interface bridge port> add bridge=bridge interface=ether12
failure: device already added as bridge port