The following is a complete list of ports that 3CX PhoneSystem uses in a default installation scenario:
Protocol Port (Default) Description
TCP 5000 or 80 v14: This port can be configured when Webserver is Abyss. On IIS it is fixed to 80 v12.5: This port can be configured by the administrator. v12: The port used for the 3CX Management Console, Presence Updates for 3CX Phone V12 (and 3CX MyPhone V11), the 3CX Hotel Module, 3CX Web Reports, 3CX Wallboard – whether using Abyss or IIS.
TCP 5001 or 443 v14: This port can be configured when Webserver is Abyss. On IIS it is fixed to 443 v12.5: This port can be configured by the administrator. v12 (Optional):  The port used for the 3CX Management Console, Presence Updates for 3CX Phone V12, the 3CX Hotel Module, 3CX Web Reports, 3CX Wallboard – whether using Abyss or IIS.
UDP & TCP 5060 3CX Phone System (SIP)
TCP 5061 3CX Phone System (SecureSIP) TLS
UDP & TCP 5090 3CX Tunnel Protocol Service Listener
UDP 9000-9255 (default) 3CX Media Server (RTP) – WAN audio/video/t38 streams
UDP 9256-9500 (default) External media transmission for 3CX WebRTC
TCP 4516 V12.5 Port used for Data communication for Wallboard