VPN Reselling 101: How to Address Firewall Port Mapping for Customers?

According to a 2024 report, cybercrime is expected to cost businesses over $10.5 trillion annually by 2025. VPNs help protect against online threats, but they need to work properly. Understanding firewall port mapping ensures that customers get the best performance from their VPN services.

When you’re in the VPN reselling business, support calls tend to fall into patterns. More often than not, the VPN isn’t the issue. The real culprit? Firewall port mapping.

If you don’t understand what that is or worse, if your customers don’t, you’ll end up shouldering blame for connectivity problems that have nothing to do with your VPN infrastructure. This guide breaks down what firewall port mapping actually is, how it interacts with VPN traffic, and what you should be telling your customers to fix it.

What is Firewall Port Mapping?

Think of it as a gatekeeper.

Firewall port mapping is the process of directing external traffic to a specific internal service behind a firewall or NAT device. Whether it’s a game server, remote desktop, or shared folder, traffic has to pass through the firewall first—and that’s where port mapping comes in.

A Simple Example

Let’s say your customer wants to access their home NAS remotely. The NAS listens on port 5000 internally. But from the outside? That port is closed unless the router knows to send incoming traffic to the NAS.

So, a firewall port mapping example would look like this:

• Public IP: 45.67.89.100
  
• Port 5000 → Forwarded to → 192.168.1.5 (NAS) on port 5000

That’s it. External port 5000 is now “mapped” to the NAS inside.

Common Firewall Ports to Map for VPN Customers

VPNs use different ports depending on the protocol they run on. Some of the most commonly used VPN protocols include OpenVPN, PPTP, L2TP/IPSec, and WireGuard. Each protocol requires specific ports to be open for a smooth connection.

Here are some firewall ports to map a drive for VPN users:

1. OpenVPN Ports

• UDP 1194 – This is the default port for OpenVPN. It provides fast and secure VPN connections.
• TCP 443 – Used when UDP 1194 is blocked by firewalls. This port is also used for HTTPS traffic, so it’s rarely restricted.

2. PPTP Ports

• TCP 1723 – This is the main port for PPTP VPN connections.
• GRE (Protocol 47) – PPTP also requires Generic Routing Encapsulation (GRE) to be allowed.

3. L2TP/IPSec Ports

• UDP 500 – Used for Internet Key Exchange (IKE).
• UDP 4500 – Required for NAT traversal.
• ESP (Protocol 50) – Encapsulating Security Payload (ESP) should be allowed.

4. WireGuard Port

• UDP 51820 – The default port for WireGuard VPN connections.

5. SSTP Port

• TCP 443 – Since SSTP uses the same port as HTTPS, it is rarely blocked by firewalls.

If a customer’s VPN is not connecting, it is likely that one or more of these ports are being blocked. Firewall port mapping helps open these ports, allowing VPN traffic to pass through.

Port Mapping vs Port Forwarding: Are They Different?

Honestly? Not really.

In most documentation, they’re used interchangeably. That said, port forwarding is usually the term you’ll see on router UIs and support forums. Port mapping is a behind-the-scenes term, used in NAT tables and system-level configurations.

Important Note for VPN Resellers

Customers might say, “I set up port forwarding, but it doesn’t work on VPN.”

Now you know to check if the VPN tunnel is overriding routes or if split tunneling is disabled.

Don’t let the terminology trip you up. The real issue is always the data flow.

Why VPNs Break Port Mapping (and How to Fix It)

Let’s clear this up.

A VPN, by design, encrypts and tunnels traffic through a different interface. If your customer uses a full-tunnel VPN and tries to access a port-mapped service—say, their NAS—they might not get through. Why?

Because their local gateway is no longer in play, everything’s being routed through the VPN.

Workarounds You Should Know

• Use split tunneling: This allows local traffic to bypass the VPN.
  
• Define static routes on the VPN client.
  
• Suggest port forwarding on the VPN server (if supported).

Some VPNs, including white-label solutions like PureVPN, offer port forwarding support directly from the server side, reducing complexity for end-users.

Real-Life Use Cases You’ll Get from Customers

Being a VPN reseller means dealing with edge cases. A few common ones:

1. Hosting Game Servers

Gamers love low-latency connections, but hosting requires port range forwarding for gaming. Popular games often need a wide range of TCP and UDP ports opened manually.

Help them identify which game ports are needed using the port forwarding port number list available from publishers.

2. Accessing Shared Drives Remotely

This one’s trickier. Accessing shared folders outside the network means certain SMB ports need to be open:

• TCP 445
  
• TCP 139
  
• UDP 137–138
  

Your client may ask about firewall ports to map a drive or why their firewall mapped drive port isn’t working after connecting to VPN. Check if those ports are being blocked by the firewall—or if the VPN tunnel is dropping them.

Also note: Windows 10 firewalls are aggressive. There’s a reason firewall port mapping Windows 10 is a popular search.

3. File Access in Corporate Environments

This is where map drive firewall ports discussions come up. If mapped network drives disappear after VPN connects, chances are the firewall isn’t allowing NetBIOS or SMB protocols over the tunnel.

Help your clients troubleshoot by isolating VPN traffic vs local LAN paths.

How to Port Map a Firewall for VPN Customers?

Now that you understand what firewall port mapping is and why it’s important, let’s go through the steps to set it up. As a VPN reseller, you may need to guide customers through this process, so it’s important to explain it in simple terms.

Before You Begin:

• Make sure you know the VPN protocol the customer is using (e.g., OpenVPN, PPTP, L2TP/IPSec, WireGuard).
• Identify the required ports based on the VPN protocol (refer to the previous section).
• Have access to the customer’s router’s admin screen to configure port forwarding.

Step 1: Log in to the Router’s Admin Panel

Most routers have a web-based interface that allows users to manage network settings. To access it:

1. Find the router’s IP address
   • On Windows, open Command Prompt and type “ipconfig” and look for Default Gateway (usually something like 192.168.1.1 or 192.168.0.1).
   • On Mac, go to System Preferences > Network > Advanced > TCP/IP and check the Router field.
2. Open a web browser and enter the router’s IP address in the address bar.
3. Enter the login details (default username and password are often found on the back of the router). If the customer has changed these credentials and forgotten them, they may need to reset the router.

Step 2: Locate the Port Forwarding Section

Once inside the router’s admin panel, look for the port forwarding settings. This is usually found under:

• Advanced Settings
• NAT (Network Address Translation)
• Firewall Settings
• Port Forwarding/Virtual Server

Some routers may have different names for this section, so it’s important to explore the menus.

Note: If a customer reports that the router’s admin screen does not display all port forwarding rules, they may need to update their router’s firmware or check with their ISP for restrictions.

Step 3: Set Up the Port Mapping Rules

1. Create a New Port Forwarding Rule
   • Click “Add New”, “Create Rule”, or a similar option in the Port Forwarding section.
2. Enter the Required Information
   • Service Name: Enter a name like VPN_Forwarding for easy identification.
   • Port Range: Input the required firewall ports based on the VPN protocol. For example:
     • OpenVPN (UDP 1194)
     • PPTP (TCP 1723)
     • WireGuard (UDP 51820)
   • Protocol: Choose TCP, UDP, or Both, depending on the VPN protocol.
   • Internal IP Address: Enter the VPN server or user’s device IP address. This directs the traffic to the correct destination.
3. Save the Changes and Apply the Settings

After entering the details, click Save or Apply to confirm the settings. The router may restart to apply changes.

Step 4: Test the VPN Connection

After setting up firewall port mapping, the customer should test their VPN connection:

1. Restart the Router and VPN Device – This ensures the changes take effect.
2. Connect to the VPN and Check for Connectivity Issues.
3. Run a Port Check Tool – Websites like canyouseeme.org allow users to test if the ports are open.

If the VPN now connects without issues, the firewall port mapping setup was successful!

Setting Up Specific Ports for VPN Connectivity

Some customers may have special requests, such as needing a custom port for VPN access. Here’s how to handle such cases:

1. Changing the VPN Port

Some ISPs or firewalls may block common VPN ports. In this case, customers can try changing the port their VPN uses.

• How to Change Internet Port for VPN Usage:
  
  • Open the VPN software settings.
  • Look for the port configuration section.
  • Change the port to a commonly open one (e.g., TCP 443 for OpenVPN).
  • Save the changes and restart the VPN.

2. Setting Up TCP Port 10001 in Router

Some customers may require TCP port 10001 for specific applications. To open it:

• Follow the port forwarding steps mentioned earlier.
• In the Port Range field, enter 10001.
• Set the protocol to TCP.
• Enter the internal IP address of the device needing this port.
• Save and restart the router.

This allows applications that rely on TCP port 10001 to function without interference.

The Comcast Port Mapping Gotcha (10244)

Let’s call this one out.

Comcast’s firmware has port 10244 blocked by default on many gateway models. Yet, several remote access and third-party apps rely on it.

If a customer says everything works except a specific desktop or app, check this first.

Tell them to log into their Xfinity gateway and add port mapping 10244 comcast firewall in the “Advanced > Port Forwarding” section.

This alone resolves 20% of unexplained issues.

TCP or UDP? Choose Wisely

Different services require different protocols.
If you’re not sure, default to TCP. It’s connection-based and more predictable.

But games, VoIP, and video streams? They usually prefer UDP for speed.

Quick Rule of Thumb:

Service Type	Protocol Needed
RDP, SSH, HTTP	TCP
Games, VoIP, VPNs	UDP or both

Mapping Ports in Bulk: When You Need Ranges

Some setups require multiple ports. You don’t want to create 20 rules manually.

That’s where port range forwarding for gaming or servers comes in.

Example:

• Start Port: 30000
  
• End Port: 30050
  
• Protocol: UDP
  
• Internal IP: 192.168.1.100

This single rule opens all 51 ports in that block, simplifying things for users running Minecraft, CS:GO, or custom app stacks.

Tools for Testing Port Mapping

When your customer says, “I forwarded the port but it still doesn’t work,” don’t guess.

Here’s what to ask them to try:

• CanYouSeeMe.org – Simple online port checker
  
• Nmap – Advanced port scanner (use cautiously)
  
• Wireshark – For analyzing packet loss or drops
  
• Router logs – Many firewalls log dropped packets or denied connections

Get your clients comfortable with testing their own setups. You don’t need to be on every call for every blocked port.

Securing Open Ports

Port mapping exposes internal devices to the public internet. That’s the trade-off.

You need to help your clients understand how to limit exposure:

• Only map what’s necessary.
  
• Use obscure ports if possible.
  
• Block access to mapped ports from foreign IPs.
  
• Use firewall rules to allow only specific source addresses.
  
• Never leave administrative interfaces exposed. Ever.

It’s your responsibility as a VPN reseller to educate, not just sell.

Troubleshooting Common Issues

Even after setting up firewall port mapping, customers may still face issues. Here are some common problems and how to fix them:

1. VPN Still Not Connecting

• Check if the correct ports were forwarded in the router settings.
• Ensure the internal IP address entered in the port forwarding rule matches the user’s device.
• Restart both the router and VPN client.

2. Router Does Not Save Port Forwarding Settings

• Some routers may require firmware updates to fix bugs.
• If the router’s admin screen does not display all port forwarding rules, the ISP may have restrictions. The customer should contact their ISP for assistance.

3. ISP Blocking VPN Traffic

• Some ISPs block VPN traffic. Switching to a different VPN port (such as TCP 443) may help.
• Customers can try using a VPN obfuscation feature to bypass ISP restrictions.

By troubleshooting these issues, VPN resellers can ensure their customers enjoy a smooth experience.

Summary: What VPN Resellers Need to Know

• Port mapping lets users access internal services through firewalls.
• VPNs can interfere—especially with full-tunnel mode.
• Windows 10 firewall is aggressive with mapped drive ports.
• ISPs like Comcast sometimes block high ports like 10244.
• UDP is common for gaming; TCP for standard apps.
• Use tools to test, not guess.
• Secure every open port. No exceptions.

This isn’t about sounding smart. It’s about keeping your customers happy and your support tickets low.

Ready to Resell a VPN With Port Mapping Support Built In?

If you’re reselling VPNs but still manually troubleshooting every port issue—there’s a better way.

Feature	Manual Setup	PureVPN White Label
Port Forwarding Support	❌ Manual	✅ Built-In
Server Management	🧑‍💻 You handle it	🛠️ We handle it
Firewall Config Support	❌ No Help	✅ Guided
Reseller Dashboard	❌ N/A	✅ Included

At PureVPN, we offer a White Label VPN solution that includes:

• Branded desktop + mobile apps
  
• Access to 6500+ servers
  
• Built-in port forwarding options
  
• Admin dashboard and reseller billing tools
  
• Zero infrastructure management on your end

You set the price. You own the customers. We handle the tech.

Final Thoughts

If you’re in the VPN reselling business, understanding firewall port mapping is a must. Many customers face connection issues due to blocked ports, and knowing how to fix them can make you a trusted provider.

• Help customers unblock VPN traffic by setting up port forwarding correctly.
• Know which ports to open based on the VPN protocol they use.
• Troubleshoot router settings to ensure a stable connection.

Providing fast and reliable VPN support will set you apart from other resellers. The more you help customers resolve issues, the more they will trust and stay with your service.

Looking for a VPN reseller program that offers strong security, great speeds, and reliable support? Join PureVPN’s reseller program today and start growing your business with a trusted VPN provider!