Simple firewall mikrotik disini yaitu menghalangi packet yang masuk ke router dan hanya port port tertentu saja yang diperbolehkan masuk ke router.
Berikut script untuk konfigurasi melalui terminal :
#Tested ROS v6.43.12
/ip firewall filter
add action=accept chain=input protocol=icmp
add action=accept chain=input connection-state=established
add action=accept chain=input connection-state=related
add action=accept chain=input comment="allow IPsec NAT" dst-port=4500 protocol=udp
add action=accept chain=input comment="allow IKE" dst-port=500 protocol=udp
add action=accept chain=input comment="allow l2tp" dst-port=1701 protocol=udp
add action=accept chain=input comment="allow pptp" dst-port=1723 protocol=tcp
add action=accept chain=input comment="allow sstp" dst-port=443 protocol=tcp
add action=drop chain=input in-interface-list=!LAN