VPS IPsec Tunnel + API Gateway Integration Between Perfex CRM and External Provider

Project Overview

I need an experienced server administrator / DevOps engineer to set up a secure architecture that allows my Perfex CRM (hosted on shared hosting) to communicate with an external payment or billing provider that requires an IPsec VPN tunnel.

Since my shared hosting environment does not support VPN or IPsec, the solution MUST involve using my VPS as a secure gateway between both systems.

What the Project Requires
1. Configure a Secure IPsec VPN Tunnel (on my VPS)

The VPS will act as the tunnel endpoint that connects to the external provider.
The developer must set up a fully working IPsec tunnel according to the provider’s requirements, including authentication, encryption standards, and all security policies.

2. Create a Reverse-Proxy/API Gateway Layer

Because Perfex CRM is hosted on shared hosting, the VPS must function as a middle layer that:

Receives encrypted API requests from the external provider through the VPN tunnel

Forwards these API calls securely to my Perfex CRM on shared hosting

Returns responses back through the VPS to the provider

This ensures my shared hosting CRM can participate in a VPN-based integration even though it does not support VPN/IPsec directly.

3. Configure HTTPS Endpoints on the VPS

The VPS must expose public HTTPS URLs for the external provider (via SSL certificates).
These endpoints will internally route traffic to the CRM system.

4. End-to-End Integration Testing

The freelancer must perform and confirm:

Tunnel connectivity and stability

Successful API request flow from provider → VPS → CRM

Successful response flow from CRM → VPS → provider

Overall system reliability under the required conditions

5. Final Documentation

Once the setup is complete, I need clear documentation covering:

High-level explanation of how the architecture works

All relevant configuration details

API routing diagram

Any required maintenance procedures

Required Skills

Experience configuring IPsec VPN tunnels

Strong knowledge of Linux server administration

Understanding of API gateways and traffic forwarding

Experience integrating external payment or billing providers

Knowledge of Perfex CRM is a plus (not mandatory)

Goal

The final result should allow my existing Perfex CRM (hosted on shared hosting) to work seamlessly with a third-party provider that requires:

A static IP

A secure IPsec connection

Protected communication paths

Encrypted API traffic

All without moving Perfex CRM from shared hosting.