Hi,
This is Sajib. Want to help how to block Imo, Whatsapp, Viber in Mikrotik router.Please co-operate me.
Hi,
As I said in another topic, this is going to be very difficult with a Mikrotik product. (other advanced FW/UTM products might detect “signatures” on this traffic identifying them more precise!)
For “Whatsapp” there you may want to read : http://forum.mikrotik.com/t/block-whatsapp/68321/1
However, there is this link (https://www.whatsapp.com/cidr.txt) which USED to have all PUBLIC IP’s of Whatsapp so you could block them. Unfortunately they stopped providing this info to everyone since Whatsapp is now under the Facbebook platform and not FREE anymore I guess 
For Viber the same story, I cannot find any references to a list of public IP’s they use on their platform.
Blocking this on L7 with Mikrotik will be very, very hard I guess.
Same for IMO (imo.im), probably running on public cloud platforms like AWS or something again you need to “block” it at another level. DNS ?
(make IMO-call and analyze what happens, what DNS-requests are made etc etc)
Perhaps there is the DNS way, are you using Mikrotik DNS server or “Pihole” system to clean DNS ? Perhaps you could just filter the whatsapp/vibers domains etc. With Pihole you can make first analysis of used domains and then put them on the blacklist. But you must make sure no DNS-resolving can be “bypassed”
Blocking using DNS are easy to overcome. Just add a host mapping.
https://play.google.com/store/apps/details?id=dns.hosts.server.change
Why?
Bandwidth limitation.
Governmental control.
Other.
True to some extend, if the endpoint (PC or mobile) is not controlled in any way by some IT-policies in a corporate environment.
If this question is for public users (eg. topicstarter is an ISP) yeah then forget about my DNS proposal because that’s not going to work.
The main conclusion is that Mikrotik is just not the correct product for these kinds of complex controls. You need other tools.