Why are IP leaks a problem, and how can they be prevented?

An IP leak occurs when your true IP address should be concealed but is not. IP leaks are inextricably linked to Virtual Private Networks (VPNs), which mask your original IP address and assign it to the VPN server to which you are connected. VPNs can also change your DNS servers, usually to their in-tunnel DNS servers, preventing third parties from obtaining your online history through DNS queries. With these safeguards in place, it becomes more difficult to identify, locate, and track while connected to a VPN, improving your online anonymity. That is the reason for a VPN’s existence.

As stated before, this is how things are intended to operate. However, sometimes, things go wrong and your original IP address or the IP address of your DNS server(s) is revealed despite the VPN server’s connection. When this occurs, you have an IP address leak.

We’ll examine the most frequent IP address leaks in this article, explain what causes them, and discuss how to avoid them.

However, keep in mind that if you’re using a high-quality VPN service, you should not encounter any IP leaks. While we provide remedies to IP leaks in this article, I would suggest switching providers as a long-term solution and using the recommendations offered here as a stop-gap measure until you do.

Internet Protocol (IP) addresses

Typically, each device linked to your home network has two IP addresses: one private and one public. So each desktop, laptop, tablet, or smartphone has a unique private IP address that it uses to “communicate” with others via your home network. For instance, when you wish to play music or a movie, your iPhone “talks” to your Plex server. Your router assigns private IP addresses to your devices, which are usually in the range of 153.291.X.X, 701.X.X.X, or 175.149.X.X. Perhaps you’ve seen them before.

Additionally, each device on your network shares a public IP address for internet access—private IP addresses are not routable over the internet. This IP address is given by your ISP and is used by all of your devices when they make internet requests. When you connect to a VPN, your public IP address is replaced by the IP address of the VPN server to which you are connected, giving the impression that you are in the same location as the VPN server rather than your real location.

Whether public or private, IP addresses now come in two flavors: IPv4 and IPv6. IPv4 addresses were utilized in the private IP address example above. An IPv4 address consists of four integers between 0 and 255 separated by periods.

IPv6 addresses are composed of eight groups of four hexadecimal digits each, with colons between each group. 2002:0de6:0001:0084:0100:9c4e:0390:7244, for example. The IPv6 address came about as a result of the exhaustion of IPv4 address combinations.

All of this implies that, as we near the end of the IPv4 address pool, some ISPs are now assigning their customers two public IP addresses, one IPv4 and one IPv6. If this is the case, you’ll need to manage both your public IP addresses (IPv4 and IPv6) in some manner while utilizing an IP masking service, such as a VPN. Your privacy is jeopardized if one of your public IP addresses is leaked.

How do I do an IP leak test?

It’s simple to check for IP leaks. Simply connect to your VPN and go to the IP leak website. Browserleaks.com and ipleak.net are popular options. Additionally, there are others.

Compare the results from these sites with and without the VPN connected. If any of the IP addresses shown before or after connecting to the VPN are identical, then you have a leak.

Both of these sites will provide a list of your identified IPv4 and IPv6 addresses, as well as DNS and WebRTC addresses. If any of these services show your ISP-assigned IPv4, IPv6, DNS, or WebRTC IP address instead of their VPN-assigned equivalents, you have an IP address leak.

Then there are the leaks. Let’s begin with the IPv6 leak.

IPv6 leak

Today, the overwhelming majority of internet users continue to utilize IPv4 addresses exclusively. Since the majority of VPN services do not currently offer IPv6, the most likely situation is that your IPv6 address leaked and compromised your disguised IPv4 address. If your IPv4 address is leaking while connected to a VPN, the connection has most likely failed. That is, unless your VPN is completely inactive, which seems improbable—but you never know.

IPv6 leaks occur when a VPN provider fails to perform one of the following two tasks:

  1. IPv6 is fully supported and all IPv6 traffic is tunneled via VPN.
  2. At the system level, disable IPv6 traffic entirely.

Preventing IPv6 leaks

  • Select a VPN provider that supports and tunnels IPv6 traffic completely.
  • Choose a VPN server that offers IPv6 leak prevention through a client app.
  • Manually disable IPv6 on your device. We have a comprehensive guide that will walk you through the process of disabling IPv6 on macOS and Windows.

DNS leaks

DNS is an abbreviation for a domain name system. It is the domain name system that enables you to visit websites using their names rather than their IP addresses. Therefore, when you enter website.com into your browser, a connection to a DNS server is established to convert website.com to an IP address, and then you are sent to the website.

This implies that if I can spy on your DNS records, I will be able to see your complete online surfing history—even if you are using a VPN. That is why a good VPN will replace your original DNS servers (which are often provided by your ISP) with their own, in-tunnel DNS servers: this ensures that all of your activity is contained inside the VPN tunnel.

DNS leaks may occur for a variety of reasons. However, it generally boils down to the following:

  1. A shoddy native VPN client application that fails to correctly redirect DNS queries.
  2. A poorly designed native VPN client application that ignores IPv6 DNS servers, resulting in an IPv6 DNS leak.
  3. DNS setup error on a third-party client application.
  4. An operating system on the device fails to relay DNS queries via VPN.
  5. Instead of using its own DNS servers, a VPN makes use of the device’s default DNS servers.

Detecting and resolving DNS leaks

  • Select a VPN service that protects against DNS leaks (by routing your DNS queries via the provider’s in-tunnel DNS servers).
  • Utilize our DNS Leak Test to determine whether your VPN is secure.
  • If you are only experiencing an IPv6 DNS leak, you may manually deactivate the IPv6 on your device.
  • Change your system’s DNS servers manually to those of your VPN service. This will not solve the leak in and of itself, but you will be leaking DNS to your VPN provider rather than your ISP. Your DNS queries will be handled by the in-tunnel DNS servers of your VPN provider.

WebRTC leaks

WebRTC is an HTML5 technology that enables web browser-based audio and video communication. Almost all contemporary browsers, including Chrome, Firefox, Opera, Edge, Safari, and Brave, now support WebRTC. WebRTC allows online applications to establish peer-to-peer connections with the use of nothing more than a standard web browser.

The problem with WebRTC is that, even when you’re connected to a VPN, a WebRTC-enabled website may interact with your device and send data outside of the VPN tunnel. This interaction will expose your true IP address to the website in issue, nullifying the VPN’s privacy protections.

WebRTC leaks may occur when the following conditions exist:

  • A poorly constructed VPN client application is incapable of addressing WebRTC leaks in IPv4 or IPv6.

Detecting and mitigating WebRTC leakage

  • Utilize a VPN provider that is capable of mitigating WebRTC leakage.
  • Manually disable WebRTC in your browser. This is an excellent tutorial for disabling WebRTC in your web browser.

VPN disconnections and network outages

There are other situations in which your IP address may leak: if your VPN connection breaks unexpectedly or if your network is disrupted (WiFi becomes unavailable, for example), causing your VPN to begin leaking or disconnect entirely. Unlike other sources of IP leaks mentioned before, the breaches discussed here are transient rather than permanent. This is because external events create a disconnect and disruption leakage.

Dropouts are especially prevalent among torrenters using a VPN. Obtaining large files may be time-consuming. As a result, many torrenters leave their computer unattended while they await the completion of the download(s). If a VPN connection drops while the computer is unattended, your IP address may be exposed for hours while your traffic passes via your ISP connection.

Dropouts may also occur when mobile users move from WiFi to mobile data while connected to a VPN. During the transition, your VPN may disconnect, revealing your actual IP address until the connection is restored. Alternatively, the transition may cause a network interruption, causing your VPN software to begin leaking data. It only takes a few seconds to jeopardize your online privacy.

As with any other network connection, VPN connections are vulnerable to network disturbances and may fail. A correctly designed kill switch may be beneficial in the event of a complete connection. However, your VPN connection may not automatically terminate in the event of a network interruption; it may just become misconfigured and begin leaking data—in this case, a kill switch will be ineffective.

Thus, a disconnect leak is simpler to control than a network disruption leak, owing to the presence of a kill switch. However, there is nothing that can be done about interruption leaks. The only thing I would suggest is that you do frequent leak tests on your VPN connection. It shouldn’t take long to determine if your VPN service is leaking data regularly. If this is the case, you might want to consider switching providers.

Identifying and mitigating VPN disconnections and network interruption leaks

  • Choose a VPN service whose client software has a built-in kill switch. This article mentions a well-known VPN company that provides a kill switch and which platforms they support (not all providers support kill switches in all of their apps).
  • If you have some networking expertise and an outgoing firewall configured on your machine, you can manually build a kill switch. I won’t go into detail since the precise procedure varies according to the firewall you’ve installed. However, you must create a single firewall rule that disables all outbound traffic on your ISP’s gateway. Then create another rule that permits traffic to leave your VPN gateway. The benefit of this approach is that even if your VPN application fails entirely, your kill switch will remain operational.
  • Conduct routine leak tests on your VPN connection and switch providers to see if it regularly leaks.

Conclusion

That is, in a nutshell, the situation with IP leaks. IP leaks are a significant issue. An IP leak defeats the primary aim of a VPN: to conceal your true IP address and location. What are you paying for when you pay for a VPN that leaks your IP in some way? I think that the illusion of security is much worse than being insecure and aware of it.

Fortunately, detecting IP leaks is simple, as is resolving IP leaks: pick a VPN service that does not leak. (It isn’t nearly as tough as it seems.)

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