/ip firewall filter
add action=drop chain=forward dst-address-list=Facebook src-address=192.168.50.0/24 comment="Blocking Facebook on RouterOS using Address-Lists"

/ip firewall address-list
add address=146.88.59.0/24 list=Facebook
add address=74.119.76.0/22 list=Facebook
add address=45.64.40.0/22 list=Facebook
add address=69.63.176.0/20 list=Facebook
add address=31.13.64.0/18 list=Facebook
add address=66.220.144.0/20 list=Facebook
add address=69.171.224.0/19 list=Facebook
add address=103.4.96.0/22 list=Facebook
add address=173.252.64.0/19 list=Facebook
add address=173.252.96.0/19 list=Facebook
add address=179.60.192.0/22 list=Facebook
add address=204.15.20.0/22 list=Facebook
add address=31.13.24.0/21 list=Facebook
add address=199.201.64.0/22 list=Facebook
add address=185.60.216.0/22 list=Facebook
add address=157.240.0.0/16 list=Facebook
add address=129.205.94.0/23 list=Facebook