Objetivo. Bloquear el acceso a una IP local desde internet: Chain: forward
In order to block a specific IP address, you need to add a Firewall filter rule.
Step-by-step guide. Follow these steps to add filter rule using Winbox:
/ip firewall filter add chain=forward src-address=1.1.1.1 action=drop
Chain “input” limit the connection to the device itself. To limit traffic going through the device use chain “forward”. Please refer to the Building Your First Firewall