Is Our IP Validation System Just Drunk, Showing Wrong Regions – Cache or Deeper Bug?

Hey Ji-hoon Sato, It's a common challenge when dealing with IP geolocation accuracy, and it definitely impacts geo-targeting data. Your suspicion about either a stubborn cache or a deeper bug is valid. While caching (ISP-level, CDN, or even local DNS) can indeed present stale IP data, leading to incorrect regional assignments, persistent discrepancies often point to issues with the underlying IP validation system or its data source. IP geolocation databases are constantly updated, but they can lag behind ISP IP block reassignments, especially in dynamic environments. Users on VPNs or proxies will also inherently show a different location than their physical one. To diagnose this, first, identify the specific IP geolocation service or database your system is leveraging. Services like MaxMind GeoIP2, Neustar IP Intelligence, or IP2Location are common. Verify their update frequency and data freshness. If your system is using an older, static database, that's a prime candidate for inaccuracy. You might also want to cross-reference a few problematic IPs with multiple independent IP lookup tools to see if the discrepancy is consistent across different providers. If the issue persists after clearing any relevant caches and confirming the data source is up-to-date, then it's worth investigating your system's integration with that service for potential misconfigurations or processing errors. What IP geolocation provider are you currently using for your validation system?