Port 5060 TCP and UDP for messaging called SIP.
- Ports UDP 16384: 32768 To allow RTP traffic for audio streams.
Other Recommendations for the Network Configuration
- Contact your ISP to assign a DMZ in order to locate the router or phone, and put your provided gateway into the "Bridge mode."
- Connect all VoIP devices and switches over the router.
- Deactivate: SIP ALG and UPnP (Universal).