How to block the Whatsapp Android application in a network

I need to block the users from accessing Whatsapp Android application who have logged in to my network. I tried to take Wireshark logs and tried to find the server's IP Address and port number, but I couldn't find any clue. Actually I am naive to Wireshark usage and network administrator domain too, so suggestions would be great!

I have a Basic Netgear Router installed in my workplace with an internet connection.

Solution 1:

c.whatsapp.net - WhatsApp Sever which is used for connection.

WhatsApp connects first then logs in then reading/writing data will be done. So blocking this stops at the initial stage.

Solution 2:

Apply a filter using the official IP list: https://www.whatsapp.com/cidr.txt, which (as of 2018-02-018) directs you where to get the list:

Dear partners, Please note that we have migrated the latest IP pools of WhatsApp to Facebook Mobile Partner Portal. Feel free to browse to the Settings page of the portal and download the latest WhatsApp IP pool: https://fb.me/mpp_support

Further IP pool updates are also done through the portal and are no longer distributed via email or through WhatsApp web site. If you have not yet registered on the Mobile Partner Portal or have difficulties accessing it - please request access through the following form and we'll be happy to assist: https://fb.me/mpp_access

For any technical requests please contact us through the Support section of the portal: https://fb.me/mpp_support

WhatsApp team

Use QoS instead of blocking.