DRAG DROP
A company deploys an Office 365 tenant. All employees use Skype for Business Online.
You need to configure the network firewall to support Skype for Business Online.
Which ports must you open? To answer, drag the appropriate port number to the correct feature or features. Each port number may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content.
Answer: 
Explanation:
Transport Control Protocol(TCP), User Datagram Protocol(UDP) ports, and Protocol Numbers are important to TCP/IP networking, intranets, and the Internet. Ports and protocol numbers provide access to a host computer.
However, they also create a security hazard by allowing uninvited access. Therefore, knowing which port to allow or disable increases a network’s security. If the wrong ports or protocol numbers are disabled on a firewall, router, or proxy server as a security measure, essential services might become unavailable.
Port 443 is used for Audio, video and application sharing sessions as well as data sharing sessions – For HTTPS.
Port 5223 is used for mobile push notifications – Extensible Messaging and Presence Protocol (XMPP) client connection over SSL.