Enable External Access to a PostgreSQL Database

Introduction

This tutorial shows how to use a Network Load Balancer (NLB) to access a PostgreSQL database hosted in a private LAN within the IONOS Cloud. The database instances are connected to a private LAN; hence, NLB acts as a reverse proxy, forwarding traffic from a public IP address to the private IP address of the database. This setup lets you connect using your existing tools and workflows from outside the IONOS Cloud environment.

Overview

This tutorial demonstrates the use of the following:

Component	Description
Virtual Data Center (VDC)	Provides an isolated cloud environment to deploy the PostgreSQL database.
PostgreSQL Database	The database instance is running privately and is accessible only within the VDC's internal network.
NLB	Acts as a reverse proxy to route traffic from a public IP address to the private database.

Before You begin

To enable secure external access to a PostgreSQL database in the IONOS Cloud using an NLB, ensure you have the following configuration values:

Component	Value (Example)	Purpose
Public Listener IP	85.x.x.x	Public IP address assigned to the NLB.
Listener Port	5432	Port exposed on the NLB for PostgreSQL access.
Target Private IP	10.7.226.4	Internal IP address of the PostgreSQL database.
Target Port	5432	Port on which the database listens.
Protocol	TCP	Network protocol used by PostgreSQL.
LAN (Database Subnet)	LAN 1	Private LAN where the database is hosted.
NLB LANs	LAN 3 (Public), LAN 2 (Private)	LANs connected to the NLB—one for public access, one for internal routing.

Note: In this setup, we assume you already have a VDC in the IONOS Cloud with a PostgreSQL database connected to a private LAN.

Reserve IP Addresses

Prerequisite: Before proceeding, ensure you have a free public IP address. This address will be assigned to the NLB, so it can receive external traffic. For more information, see Reserve an IPv4 Address.

Execution

The configuration enables the NLB to forward external PostgreSQL traffic to your private database instance. The execution process is divided into the following steps:

Create an NLB

To create a Network Load Balancer that acts as a reverse proxy to connect to your PostgreSQL database, follow these steps:

1. In the DCD, open the data center where your PostgreSQL is already deployed.

2. Drag the Network Load Balancer element into the workspace.

3. In the Settings tab, configure the following:

• Primary IPv4: Assign the public IP address reserved earlier to enable external access.

Network Load Balancer Settings

4. In the Forwarding rules tab, create a rule by providing the following information:

• Name: A name for your forwarding rule.

• Algorithm: Round Robin.

• Protocol: TCP.

• Listener IP: The public IP address.

• Listener Port: 5432.

5. Select Create to create the forwarding rule.

Result: A forwarding rule is successfully created.

Network Load Balancer Forwarding rule Settings

6. Select Add target to add targets for your forwarding rule and provide the following information:

• Target IP: Internal IP address of the PostgreSQL database.

• Target Port: 5432.

• Weight: 1.

• Proxy Protocol: none.

7. Select Add Target to create the new target.

Result: A target is successfully created for your forwarding rule.

Network Load Balancer Add target Settings

8. Provision your changes.

Result: The NLB has been successfully created. You can now access the PostgreSQL instance through the public IP address attached to the load balancer.

Verify connectivity

To confirm that the external connection to your PostgreSQL database is working, use a terminal or PostgreSQL client from your local system:

nc -vz <85.x.x.x> 5432

Replace the following:

• <85.x.x.x> with your public IP.

Result: You see the database is accepting connections.

Connection to 85.x.x.x 5432 port [tcp/postgresql] succeeded!

Summary

You have successfully configured secure external access to a Managed PostgreSQL database hosted in the IONOS Cloud by using an NLB. The NLB acts as a reverse proxy, forwarding traffic from a public IP address to the private database located in your VDC.