PBX SIP and IAX Communication
| PORT | TCP/UCP | PURPOSE | CHANGING PORT | SECURITY | NOTES |
| 5060 | UDP | chan_PJSIP Signaling | Can change this port inside the PBX Admin GUI SIP Settings module. | Not recommended to open this up to untrusted networks. | Standard Port used for chan_PJSIP Signalling. |
| 5061 | chan_PJSIP Secure Signaling | Can change this port inside the PBX Admin GUI SIP Settings module. | Not recommended to open this up to untrusted networks. | Secure Port used for chan_PJSIP Signalling. | |
| 5160 | UDP | chan_SIP Signaling | Can change this port inside the PBX Admin GUI SIP Settings module. | Not recommended to open this up to untrusted networks. | Standard Port used for chan_SIP Signalling. |
| 5161 | chan_SIP Secure Signaling | Can change this port inside the PBX Admin GUI SIP Settings module. | Not recommended to open this up to untrusted networks. | Secure Port used for chan_SIP Signalling. | |
| 10000-20000 | UDP | RTP for SIP | Can change this port inside the PBX Admin GUI SIP Settings module. | Safe to open to the outside world and is required by most SIP Carriers as your RTP traffic can come from anywhere. | Used for the actual voice portion of a SIP Call. |
| 4569 | UDP | IAX | Can change this port inside the PBX Admin GUI IAX Settings module. | Not recommended to open this up to untrusted networks. | Used for IAX protocol and trunking |
| 4000-4999 | UDP | FAX UDPTL | Not configurable in the GUI, on by editing custom conf file. | Used for T38 fax media |
Zdroj> https://wiki.freepbx.org/display/PPS/Ports+used+on+your+PBX