La opción muy potente para tí!
Mikrotik creará un nuevo Scheduler y pondrá automática 
todos los DNS de  Whatsapp en Address-List de MikroTik!!

*****COPY********

/system scheduler
add comment="Whatsapp Blocker" interval=2m name="Whatsapp Blocker" on-event="#\
\_Use DNS Entrys and add Address to the Firewall Address-list #\r\
\n:foreach i in=[/ip dns cache all find where (name~\"whatsapp\") && (type\
=\"A\") ] do={\r\
\n :local tmpAddress [/ip dns cache get \$i address];\r\
\ndelay delay-time=10ms\r\
\n# prevent script from using all cpu time #\r\
\n :if ( [/ip firewall address-list find where address=\$tmpAddress] = \
\"\") do={ \r\
\n :local cacheName [/ip dns cache get \$i name] ;\r\
\n :log info (\"added entry: \$cacheName \$tmpAddress\");\r\
\n /ip firewall address-list add address=\$tmpAddress list=Whatsapp co\
mment=\$cacheName;\r\
\n}\r\
\n}" policy=ftp,reboot,read,write,policy,test,password,sniff,sensitive \
start-time=startup

*****FIN********

Ahora debes Crear una nueva Firewall Filter Rule para que tenga efecto!

/ip firewall filter 
add chain=forward action=drop dst-address-list=Whatsapp disabled=no comment="Whatsapp Blocker"

Cuando tu Red es un Hotspot:

/ip firewall filter 
add chain=forward action=jump jump-target=hs_whatsapp_filter dst-address-list=Whatsapp comment="JUMP TO hs_whatsapp_filter " disabled=no
add chain=hs_whatsapp_filter action=drop comment="ACTION = DROP WHATSAPP" disabled=no

Fuente: http://forum.mikrotik.com/

Editado by: Rodrigo Anrrango 
http://configurarmikrotikwireless.com/