Does anyone know of a free web service to determine the zip code of an IP address?
MaxMind GeoLite City
I realize this question is old, but this may still help other people. I found a free / open source (so you can even run your own instance and not be subject to their hourly limit of 10,000 requests) IP geolocation database: http://freegeoip.net/
I don't know of any that will return a zipcode, but this one is free and returns city/state
is a free geolocation service also it is way awsome in quality
来源：https://stackoverflow.com/questions/1828334/free-web-service-to-determine-ip-address-zip-code