Description:
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Currently, filter_var is able to filter out private IP addresses and those reserved by protocol with the FILTER_FLAG_NO_PRIV_RANGE and FILTER_FLAG_NO_RES_RANGE flags respectively.

There is a need for further filtering, to determine whether an IP address is Global, as described in RFC 6890.

Only global addresses are useful in identifying the country of origin; this new filter would enable PHP code to search through the list of addresses in an X-Forwarded-For header to find the first global address and send only that address to a country locator such as GeoIP.

Global addresses would also be useful for forensic purposes.

This request is for a new flag, perhaps called FILTER_FLAG_ONLY_GLOBAL_RANGE, that would filter out all IP address ranges listed as “Global: false” in RFC 6890.