How to Set Up and Manage a Site-to-Site VPN Between Your Brisbane Office and Home Office

Network & Internet KB-1099

Summary

This guide helps you troubleshoot and resolve: How to Set Up and Manage a Site-to-Site VPN Between Your Brisbane Office and Home Office. Follow the steps below to fix the issue.

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Common Causes

A Site-to-Site VPN creates a permanent, encrypted tunnel between your Brisbane office network and your home office network. This allows staff working from home to access shared drives, printers, and internal servers as if they were physically sitting in the office. This guide walks you through setting up and managing the connection using standard business-grade routers.

Before You Begin

You will need administrative access to the routers at both locations, the public IP addresses for each site, and a shared pre-shared key (PSK) for authentication. If your internet service uses CGNAT or you do not have a static public IP, contact your ISP or Open a Ticket for assistance. Consider using a Dynamic DNS service if your public IP address changes periodically.

Setup Instructions

Step 1: Gather Network Information

Record the following details for both locations:

Public IP address (WAN IP) of each router
Local subnet (e.g., 192.168.1.0/24 for Brisbane office, 192.168.2.0/24 for home office)
Router admin username and password
A strong pre-shared key for VPN authentication

Avoid using the same subnet at both sites. If both offices use 192.168.1.0/24, traffic will not route correctly across the tunnel.

Step 2: Configure the Brisbane Office Router

Open a web browser and enter the router's gateway address (commonly 192.168.1.1 or 192.168.0.1).
Log in with your administrator credentials.
Go to VPN > Site-to-Site VPN or Security > VPN, depending on your router model.
Select Add or Create New Tunnel.
Set the connection type to IPSec or IKEv2.
Enter the remote gateway as the public IP address of your home office router.
Enter your pre-shared key in the Authentication or PSK field.
Set the local subnet to your Brisbane office network (e.g., 192.168.1.0/24).
Set the remote subnet to your home office network (e.g., 192.168.2.0/24).
Save the settings and enable the tunnel.

Step 3: Configure the Home Office Router

Log into the home office router admin interface.
Navigate to the same VPN or Security section.
Create a new Site-to-Site tunnel.
Enter the public IP address of your Brisbane office router as the remote gateway.
Use the exact same pre-shared key entered at the Brisbane office.
Set the local subnet to your home office network.
Set the remote subnet to your Brisbane office network.
Save and enable the tunnel.

Step 4: Update Firewall Rules

Ensure both routers allow traffic through the VPN tunnel:

Permit ESP and UDP port 500 / 4500 through the WAN firewall.
Allow traffic between the local and remote subnets in the LAN firewall rules.
If using Windows Defender Firewall on file servers, create inbound rules to allow file sharing from the remote subnet.

Step 5: Test the Connection

From a computer at the home office, open Command Prompt or Terminal.
Ping a device on the Brisbane office network (e.g., ping 192.168.1.10).
If successful, attempt to access a shared folder using the UNC path (e.g., \\192.168.1.10\SharedFolder).
Repeat the test from the Brisbane office to a device at the home office.

Managing Your VPN

Monitoring Tunnel Status

Most business routers display the VPN tunnel status in the admin dashboard under VPN > Site-to-Site. Look for indicators such as Connected, Established, or Up. If the status shows Down or Negotiating, the tunnel is not active.

Updating Subnets

If you add a new VLAN or change your office IP range, update the local and remote subnet settings on both routers. Mismatched subnets are the most common cause of VPN traffic failure.

Rotating Pre-Shared Keys

For security, change your pre-shared key periodically. You must update the key on both routers simultaneously, or the tunnel will drop until both sides match.

Troubleshooting

Tunnel Will Not Connect

Verify both routers have stable internet connections.
Confirm the public IP addresses entered are correct and current.
Check that the pre-shared key matches exactly on both sides.
Ensure UDP ports 500 and 4500 are not blocked by your ISP or firewall.
Confirm your ISP does not block VPN protocols such as ESP or IKE.

Tunnel Connects but No Traffic Passes

Double-check the local and remote subnet configurations on both routers.
Confirm firewall rules permit traffic between the subnets.
Check for IP address conflicts between the two networks.
Test with ping and tracert to identify where traffic stops.

Slow Performance Over VPN

Run a speed test at both locations to rule out local internet issues.
Encryption overhead can reduce throughput; avoid transferring very large files over the tunnel during business hours.
If using consumer-grade routers, consider upgrading to business hardware with hardware-accelerated VPN.

Do not expose VPN management ports to the public internet unless strictly necessary. Restrict admin access to trusted IP addresses where possible.

If you are unable to establish the tunnel after following these steps, Open a Ticket and our Brisbane support team can assist with your configuration.

For help connecting devices to your local wireless network, see How to connect to Wi-Fi

Still Having Issues?

Need more help? If the issue persists after trying these steps, please open a support ticket and our team will assist you.

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