/ ip firewall filter 
add chain=input protocol=tcp psd=21,3s,3,1 action=add-src-to-address-list \
    address-list="port scanners" address-list-timeout=2w comment="Port \
    scanners to list " disabled=no 
add chain=input protocol=tcp tcp-flags=fin,!syn,!rst,!psh,!ack,!urg \
    action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w comment="NMAP FIN Stealth scan" disabled=no 
add chain=input protocol=tcp tcp-flags=fin,syn action=add-src-to-address-list \
    address-list="port scanners" address-list-timeout=2w comment="SYN/FIN \
    scan" disabled=no 
add chain=input protocol=tcp tcp-flags=syn,rst action=add-src-to-address-list \
    address-list="port scanners" address-list-timeout=2w comment="SYN/RST \
    scan" disabled=no 
add chain=input protocol=tcp tcp-flags=fin,psh,urg,!syn,!rst,!ack \
    action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w comment="FIN/PSH/URG scan" disabled=no 
add chain=input protocol=tcp tcp-flags=fin,syn,rst,psh,ack,urg \
    action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w comment="ALL/ALL scan" disabled=no 
add chain=input protocol=tcp tcp-flags=!fin,!syn,!rst,!psh,!ack,!urg \
    action=add-src-to-address-list address-list="port scanners" \
    address-list-timeout=2w comment="NMAP NULL scan" disabled=no 
add chain=input src-address-list="port scanners" action=drop comment="dropping \
    port scanners" disabled=no