IPv6 adoption keeps climbing, and it changes how geolocation behaves. If your app still assumes IPv4, you may be misreading a growing share of traffic. Here's what's different and what to do about it.
Why IPv6 is different
- Address space: IPv6 is enormous, so allocations are sparser and blocks are larger (commonly /32 to /48 for end networks).
- Per-device addresses: devices often get their own address and rotate it via privacy extensions, so a single user produces many IPv6 addresses.
- Newer allocations: some IPv6 ranges have thinner historical data than long-established IPv4 blocks.
Impact on accuracy
Country-level accuracy for IPv6 is generally strong, but city-level data can lag IPv4 in some regions because the ranges are newer. Rotating per-device addresses also make naive "one IP = one user" assumptions break — important for rate limiting and fraud (see filtering bots).
Practical guidance
- Support both stacks; never assume the client is IPv4.
- Key on the prefix, not the full IPv6 address, for rate limiting and reputation (e.g. the /64).
- Pair with fingerprinting: when addresses rotate, a stable network/device fingerprint links sessions reliably.
- Normalize addresses before lookups and logging.
How detectip.ai handles it
detectip.ai resolves both IPv4 and IPv6 to location and threat, and its bot/AI-agent detection relies on JA4/QUIC fingerprints that don't care which IP version is in play — so rotating IPv6 addresses don't let automation slip through. Try it with a free key.
FAQ
Is IPv6 less accurate? Usually comparable at country level; city can lag in newer ranges.
Should I rate-limit per IPv6 address? No — use the prefix (e.g. /64), since one user has many addresses.