Regra que adiciona Port Scanner na lista port scanners

/ip firewall filter
add action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w chain=input comment="NMAP FIN Stealth scan" \
    protocol=tcp tcp-flags=fin,!syn,!rst,!psh,!ack,!urg
add action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w chain=input comment="SYN/FIN scan" protocol=tcp \
    tcp-flags=fin,syn
add action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w chain=input comment="SYN/RST scan" protocol=tcp \
    tcp-flags=syn,rst
add action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w chain=input comment="FIN/PSH/URG scan" protocol=\
    tcp tcp-flags=fin,psh,urg,!syn,!rst,!ack
add action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w chain=input comment="ALL/ALL scan" protocol=tcp \
    tcp-flags=fin,syn,rst,psh,ack,urg
add action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w chain=input comment="NMAP NULL scan" protocol=tcp \
    tcp-flags=!fin,!syn,!rst,!psh,!ack,!urg
add action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w chain=input comment="Port scanners to list " \
    protocol=tcp psd=21,3s,3,1

Regra que bloqueia os IP’s que estiverem na lista port scanners

add action=drop chain=input comment="Bloqueio Port Scanner" in-interface=\
    pppoe-out1 src-address-list="port scanners"

Regra contra força bruta SSH – Inclui na lista

/ip firewall filter
add chain=input protocol=tcp dst-port=22 src-address-list=ssh_blacklist action=drop \
comment="drop ssh brute forcers" disabled=no

add chain=input protocol=tcp dst-port=22 connection-state=new \
src-address-list=ssh_stage3 action=add-src-to-address-list address-list=ssh_blacklist \
address-list-timeout=10d comment="" disabled=no

add chain=input protocol=tcp dst-port=22 connection-state=new \
src-address-list=ssh_stage2 action=add-src-to-address-list address-list=ssh_stage3 \
address-list-timeout=1m comment="" disabled=no

add chain=input protocol=tcp dst-port=22 connection-state=new src-address-list=ssh_stage1 \
action=add-src-to-address-list address-list=ssh_stage2 address-list-timeout=1m comment="" disabled=no

add chain=input protocol=tcp dst-port=22 connection-state=new action=add-src-to-address-list \
address-list=ssh_stage1 address-list-timeout=1m comment="" disabled=no

Regra que bloqueia os IP’s que estiverem na lista ssh

add chain=forward protocol=tcp dst-port=22 src-address-list=ssh_blacklist action=drop \
comment="drop ssh brute downstream" disabled=no

Fontes:

https://wiki.mikrotik.com/wiki/Bruteforce_login_prevention

https://routeros.forumeiros.com/t4960-drop-port-scanners#google_vignette

Como evitar ataques de força bruta e de scanner de porta MikroTik

Como bloquear o porta scanner no MikroTik

https://under-linux.org/showthread.php?t=144768#google_vignette

https://under-linux.org/showthread.php?t=144768