Public IP and Ports Overview

This topic describes when you need to configure the Public IP and Ports settings and introduces two functions of Public IP and Ports settings.

Applications

When your PBX is connected behind a router and needs to communicate with SIP devices on the external network, you need to set Public IP and Ports settings. Public IP and Port settings can be applied to different types of networks:

Public IP Address
If your Internet Service Provider (ISP) provides a static public IP address, you can configure PBX network for remote access with the IP address.
For more information about the configurations, see Configure Network for Remote Access by a Domain Name.
External Host
If static public IP address is not available in your network environment, you must have a registered domain name, and configure PBX network for remote access with the domain name.
For more information about the configurations, see Configure Network for Remote Access by a Public IP Address.

Functions

Public IP and Ports settings have the following two functions to ensure that remote devices can access and communicate with the PBX via SIP protocol:

Solve SIP NAT issue

If your PBX is connected behind a router, it can be said that the PBX is behind a Network Address Translation (NAT) router. To allow remote devices to access the PBX, you need to set up NAT rules and port forwarding on the router. In this way, the router will forward the right inbound packets from the internet to the PBX.

SIP-based communication does not reach devices in the Local Area Network (LAN) behind firewalls and NAT routers automatically. Public IP and Ports settings on the Yeastar P-Series PBX System provide a SIP NAT solution to ensure that SIP data can be transmitted correctly between the PBX and the public internet.

Note: Yeastar P-Series PBX System doesn't support NAT feature, you need to set up NAT rules and port forwarding on your router.
NAT process

When a request is sent to the public internet, that request will have a source address consistent with the local LAN address (for example, 192.168.6.124).

That local IP address will not be publicly routable because it is a private IP address. NAT replaces the local source IP address with a public IP address which is routable on the public internet.

SIP NAT

NAT only replaces a local IP address with a public IP address for IP header in a data packet, but not for SIP headers, which may cause one-way audio issue for SIP calls or SIP registration failure.

To solve the SIP issues, you need to configure Public IP and Ports on the PBX. PBX will replace local IP address with public IP address and replace local SIP port with external SIP port before sending the packets to the public internet.

Provide PBX with information of Linkus remote access

The Public IP and Ports configurations allow Linkus remote access by solving SIP NAT issue. In addition, Yeastar P-Series PBX System can generate QR codes and links for Linkus remote access based on the information provided on the Public IP and Ports page.