What Is a VPN Passthrough? - Learn Important VPN Terminology

What Is a VPN Passthrough?

vpn passthrough

You may need a VPN passthrough and we will explain why. All VPNs employ a set of predetermined rules to connect with a remote server. These rules are called protocols. Common VPN protocols include OpenVPN, IKEv2/IPsec, WireGuard, SSTP, L2TP/IPSec, PPTP, etc.

However, some of the older protocols do not effectively work on routers. Hence, it may be impossible to simultaneously connect multiple devices to a VPN server if you are using a VPN provider running a protocol like PPTP. This issue can be frustrating. But if you want to fix the problem, you have to configure a VPN passthrough on your router.

So, in this article, we will explain VPN passthroughs. We will also look at how a VPN passthrough works.

What is a VPN Passthrough?

The term “VPN passthrough” is a router feature that lets any connected device allow VPN traffic to go through that particular router or reach a distant network. A VPN passthrough enables unrestricted movement of VPN traffic. It ensures that older VPN protocols like PPTP and LT2P do not identify and stop the traffic.

Why Some Routers Need a VPN Passthrough

For you to fully understand the term “VPN Passthrough,” you need to understand routers. There are two main types of routers. The first type of router can natively connect to a VPN. These routers support protocols such as IPsec, PPTP, and L2TP. Furthermore, you can make these routers operate as a VPN server, or you can use it to establish a site-to-site VPN with another VPN gateway. 

The second type of router cannot automatically connect to VPNs. They restrict VPN traffic since they do not natively support some VPN protocols. However, these types of routers are not common. If your router does not support VPN connections, you need a VPN Passthrough.

A VPN passthrough links two secured networks through the internet. A router or firewall’s VPN Passthrough feature enables a machine to connect to a distant network.

The Netgear WGR614 Wireless Router is the most dependable and effective router that supports VPN Passthrough. It allows three simultaneous VPN connections. The Netgear FWAG114 ProSafe is another router that supports VPN Passthrough. It supports end-to-end VPNs.

How Does a VPN Passthrough Work?

Most routers have a feature called Network Address Translation (NAT). NAT enables many LAN-connected devices to share a single public IP address. NAT is fantastic because it stands between your network and the broader internet and filters the traffic. Additionally, it ensures you only get the information you requested. Hence, this protects you from hackers and viruses. Also, it fixes a major issue with IPv4. All devices connected to your router have private IP addresses, which NAT requires to transmit the desired data.

But for the NAT to perform its function, it requires certain details about the connections leaving and entering your router. When outdated VPN protocols attempt to get through, a problem arises. The NAT is forced to block certain connections. NAT does this because the encryption method does not provide it with sufficient information to function properly. This is where a VPN passthrough comes into play. Depending on your VPN’s protocol, a VPN passthrough—also known as a PPTP passthrough or an IPsec passthrough—can be useful.

Internet Protocol Security (IPsec) Passthrough

The IPsec protocol focuses on encrypting data packets and creating secure connections. It is a layer of security built into the network itself. IPsec does not function well with  NAT protocols.

Devices not supporting IPsec out of the box can connect to a VPN via the IPsec passthrough. IPsec passthrough router devices already have this protocol built in. Hosting firms for IPsec passthrough servers allow this protocol on a VPN server. You must verify your router’s IPsec passthrough setting and input the information given to you by your VPN service provider to configure IPSec Passthrough.

Point-to-Point-Tunneling Protocol (PPTP) Passthrough

PPTP links many VPNs and permits tunneling via an IP network. PPTP is widely used in routers to allow devices to connect to the internet through NAT, even though they are incompatible. So, PPTP Passthroughs are VPN Passthroughs that create VPN tunnels using PPTP technology. The PPTP Passthrough feature allows PPTP to travel over a NAT router. Consequently, VPN clients linked to such a router establish outbound PPTP connections.

Layer Two Tunneling Protocol Passthrough

Like PPTP passthrough, L2TP passthrough creates a tunnel to any device you wish to connect to your VPN network, making it another sort of passthrough VPN.

Since all information transmitted through your connection will be encrypted and protected once it is set up, it functions like the PPTP passthrough. Ports for L2TP passthrough are necessary for this kind of connection. They can be located in the “service type” part of a port forwarding table.

Why You Should Use a VPN Passthrough

Ideally, you do not need a VPN Passthrough since a VPN passthrough is built into almost all modern routers. The security of obsolete protocols like PPTP is a major worry. An RDP (Remote Desktop Protocol) should be considered if remote access is your main goal. It offers secure access to confidential corporate resources and is simple to monitor.

However, a VPN passthrough has several benefits such as getting through a router’s firewall and reaching a distant network. Adding this feature to the router will encrypt any data delivered to the connection and keep you safe if your router supports VPN passthrough, which it should. 

How to Detect if VPN Passthrough Is Enabled on Your Router

If you are unsure if you have enabled the passthrough feature, start by checking if your router offers IPsec or PPTP passthrough choices. 

  • Next, go to the Security tab on your router’s web interface
  • From the drop-down menu, choose the VPN passthrough sub-tab
  • Verify that the L2TP (1701), PPTP (1723), and IPsec (50, 21/ 500) ports are all open
  • Contact your VPN provider if you cannot connect to a VPN

A router can only create an outbound VPN connection with the PPTP or IPSec passthrough feature. Using the above step-by-step guide, you may verify that the capability is working on your network. By encrypting the data moving between your device and your network, the VPN ensures that your private information remains private and challenging to intercept. This way, no one can see what you’re doing online.

Enabling VPN Passthrough on a Router

You must get access to your router’s settings to enable a VPN through it. Once you’ve signed in, search for the VPN passthrough section in your router’s settings. Enable the passthrough and provide your VPN provider’s details. You can now proceed after saving your modifications. 


VPN passthrough is getting less and less useful as time goes on. It was important when older VPN protocols did not function with NAT. VPN passthrough makes it possible for your router to handle older VPN protocols. While more VPNs are integrating up-to-date VPN protocols, some routers still have older protocols. But changing routers can be expensive. So, if you do not want to change your router, you can bypass it with VPN passthrough.

Frequently Asked Questions

Is VPN passthrough essential?

VPN passthrough is necessary if your router or VPN protocol is out-of-date. It will need to be upgraded or manually enabled on your router.

What is the difference between a VPN and a VPN passthrough?

To maintain your anonymity, a VPN is a program that offers data encryption and tunneling services. On a machine like a desktop computer or a smartphone, a VPN is installed. Conversely, a VPN passthrough enables unhindered VPN traffic flow, especially on routers. 

Is VPN passthrough safe?

If you are using an old VPN protocol, you require a VPN passthrough. Although they are no longer frequently used, these protocols, like PPTP and L2TP, are not secure. You can avoid using a passthrough if you utilize secure protocols like OpenVPN.

Do I need a VPN passthrough?

Most recent VPNs come with a passthrough. If yours does not, you still do not have to worry. Instead, you can just follow the tips above and set up a VPN passthrough. It is a simple process that does not require any special skills or knowledge. 

Does a VPN passthrough slow internet?

When using a VPN passthrough, your internet speed should increase rather than decrease. This is because a VPN passthrough is based on a high-speed internet connection with a steady physical connection and a quick connection speed.

Do I need to turn off VPN passthrough?

Enabling PPTP passthrough is not an issue if you want to use your PPTP connection to get the best VPN speeds and are not too worried about your online data or traffic possibly being compromised.

However, it is best to deactivate PPTP passthrough if you place a high value on online security and want to ensure that your PPTP connection does not unintentionally pass through your router. PPTP does not provide any security and is devoid of the encryption seen in other VPN protocols. This is why it is preferable to deactivate PPTP passthrough if you want to ensure that your connection stays 100 percent safe.