IPv4 vs IPv6: What they mean for your online privacy

Not all IP addresses are created equal — and the version you use can shape how easily you're tracked online. In this guide, we compare IPv4 vs. IPv6 from a privacy perspective and explain how to stay anonymous with NymVPN.

What’s the difference between IPv4 and IPv6?

IPv4 has been around since the early days of the Internet. It uses 32-bit addresses, which limits it to about 4.3 billion unique addresses. IPv6 was introduced to fix this limitation, offering 128-bit addresses and an almost infinite number of unique IPs.

While IPv6 is more modern and efficient, it can also introduce new privacy risks.

Does IPv6 expose more of your personal data?

Yes, in many cases, IPv6 can leak more metadata than IPv4. That’s because it often assigns a unique address per device, sometimes linked to your MAC address. This makes it easier to track your activity across sessions and networks.

In contrast, IPv4 often uses NAT (Network Address Translation), which groups multiple devices under one IP address, adding a small layer of obfuscation. For privacy-conscious users, IPv6 is a double-edged sword: it’s faster and more scalable, but potentially more revealing.

How to protect your IP address with a VPN

Whether you’re on IPv4 or IPv6, your IP addresses is still visible to your ISP and every site or app you use – that is, unless you’re using a VPN.

Why NymVPN?

NymVPN is very different from traditional VPNs. It runs on a decentralized mixnet, which hides not just your IP but your metadata too. By routing your traffic through multiple relay nodes and adding dummy traffic, it makes it nearly impossible for anyone to track you based on timing, IP, or volume. With Nym, you get:

• IP anonymization for both IPv4 and IPv6
• Resistance to traffic analysis
• No logs by design
• A decentralized privacy layer built for the future

Does NymVPN support IPv6?

Yes. Nym supports both IPv4 and IPv6 traffic. As IPv6 adoption increases, having a VPN that can properly handle both is critical. Some VPNs disable IPv6 or leak IPv6 traffic, but NymVPN routes everything through its privacy-preserving infrastructure.

IPv6, metadata, and surveillance: The bigger picture

It’s not just about which IP version you use — it’s about what that address reveals. IPv6’s vast space makes it easier to assign static, identifiable addresses, which are harder to rotate and anonymize.

That’s why metadata protection matters. Even if you’re using a "private" search engine or encrypted app, your IP address and routing metadata can still be used to profile you.

IPv6 also introduces persistent identifiers that can stay the same across different network connections. This means tracking isn't limited to one website or session — it can follow you across different services and times. When these identifiers are combined with fingerprinting techniques, advertisers and surveillance agencies can build a comprehensive profile of your online behavior. IPv4, while limited in address space, does not carry the same inherent risk unless statically assigned.

For a deeper dive, check out Nym’s What is metadata and why it matters.

IPv4 vs IPv6: Why it matters for privacy in 2025

As the internet evolves, so do the tools of surveillance. IPv6 adoption is growing globally, but many users are unaware that it could increase traceability. While IPv6 offers technical advantages, its ability to assign unique identifiers to individual devices poses a real risk for privacy-minded users. VPNs that fail to support IPv6 may leave you exposed. That’s why it’s essential to understand the nuances of internet protocol design. Knowing the difference between IPv4 and IPv6 isn’t just for network engineers: it’s vital knowledge for anyone who wants to reduce exposure online.