Drop invalid connections
[code]
/ip firewall filter
add chain=forward connection-state=established comment=”allow established connections”
add chain=forward connection-state=related comment=”allow related connections”
add chain=forward connection-state=invalid action=drop comment=”drop invalid connections”
[/code]
[code]
ip firewall filter
add chain=forward connection-state=new action=jump jump-target=block-ddos
add chain=forward connection-state=new src-address-list=ddoser dst-address-list=ddosed action=drop
add chain=block-ddos dst-limit=50,50,src-and-dst-addresses/10s action=return
add chain=block-ddos action=add-dst-to-address-list address-list=ddosed address-list-timeout=10m
add chain=block-ddos action=add-src-to-address-list address-list=ddoser address-list-timeout=10m
[/code]
sourec: http://forum.mikrotik.com/viewtopic.php?f=2&t=54607