We disabled IPv4 expecting a clean, modern IPv6-only setup. What we got instead was a masterclass in legacy reality.
Several third-party services silently assumed IPv4. Some APIs resolved to IPv4-only endpoints. A few SaaS tools hard-coded IP allowlists. Monitoring broke in odd ways. Even “IPv6-ready” systems occasionally failed during DNS fallback or dual-stack edge cases.
The biggest lesson? IPv6 support is often theoretical until you remove IPv4 and watch what panics.
We re-enabled IPv4 not because IPv6 failed—but because the ecosystem around us wasn’t fully there yet. For now, dual-stack gives us resilience, compatibility, and time to pressure vendors (and ourselves) to do IPv6 properly.
IPv6 is the future. IPv4 is still the present.
Comments