ISP assigned 2 IP address: Public & Private - How do I route?


I’m trying to spin-up, in a semi-lab environment, a PBX for testing. When I asked my ISP for a SIP trunk (They also provides it), they said I’ll have to also get another IP address, to be directly assigned to the PBX, which I expected to be in the same range of my regular public IP, but to my surprise, I received an IP in the range of 10.57.0.x, which is a private IP, to my understanding. I know that they should be asked that question, but our relationship is… not very communicative.

For example (IP address made up for this post):

My gateway IP is:

My current public IP is:

The IP I was given for the PBX:

Is it possible that the private IP is used only for communicating between the PBX and their trunk, creating some sort of a local networks between us?

I noticed this guide, but I’m not sure it suits this case well: pfSense® software Configuration Recipes — Routing Public IP Addresses | pfSense Documentation

As I said, this is mainly for testing and I’ll be the first to admit it’s kinda of a hobby, and I’m learning as I go, so if something doesn’t makes sense here, I do apologize.

I appreciate your help. Thank you :slight_smile:

Some ISP’s can have extra rules in their equipment to allow the private IP routing, it’s something you will have to ask them on how to setup.

Hey Tom, thank for your reply.

Yep, they are… not giving a lot of info, which makes things hard.