A Zero GeoLite Proxy Flag Does Not Prove a Direct Client
Check the MaxMind product schema and field status before treating a City lookup as an anonymous-proxy classification.
A zero in an old is_anonymous_proxy column does not establish that the IP was checked against a current comprehensive proxy list. MaxMind deprecates that attribute and directs users to Anonymous IP data.
To interpret the result, keep three inputs together: the lookup product, database build date and exact returned field. An SDK property can exist even when the database opened by the application does not supply that trait.
A City lookup answers a location question. Anonymous IP data supplies classifications such as public proxy, VPN provider, hosting provider and Tor exit. Even within that data, a hosting address is not necessarily an open HTTP proxy, and a proxy classification supplies neither its port nor its login requirements.
Preserve missing data, deprecated data and a negative classification as different states. None reveals an original client address hidden behind an intermediary.