IPv4 and IPv6 leaks are two of the five possible types of address leaks associated with virtual private networks. In simplest terms, the more general term “VPN leaks” denotes unauthorized disclosures of data which should have been protected by end-to-end encryption, i.e. tunneling protocols.
IPv6 leaks aka ‘those at realistic risk of happening’
Given how the RIPE Network Coordination Centre officially ran out of IPv4 addresses in late 2019, the still-incredibly-slow adoption of the newer IPv6 standard is all the more frustrating to witness nowadays. The fact that all too many VPN providers still don’t bother with IPv6 support means that even if your IPv4 address is fully encrypted, choosing the wrong VPN can still leave your IPv6 address out in the open, with that bit of 128-bit information being enough to identify you on its own.
IPv4 leaks aka ‘those that probably shouldn’t worry you’
While it’s possible for your VPN setup to fail even beforehand, that’s pretty unlikely to happen. In other words, a VPN service leaking IPv4 addresses is one that isn’t working in the first place, so you’d have been better off protecting your identity by renaming your computer to something like DJTrump-PC than bothering with tunneling protocols in the first place.
Even on the off chance you’re so unlucky you end up with a VPN that doesn’t work, hopefully you had enough wisdom to at least go with one that supports kill switches. Because that’s pretty much the whole reason VPN kill switches exist – to protect you from technology that will inevitably fail if given enough opportunities to disappoint you (insert_poetic_life_lesson_here).
How to check for IPv4/6 leaks
Determining whether your VPN is working as intended or leaking IP addresses that can be used to identify you is fairly straightforward. Just select your VPN testing tool of choice and you’ll have your answer in no time.