php check if IP is in given network range

ip_in_range.php

/**
 * Check if a given ip is in a network
 * @param  string $ip    IP to check in IPV4 format eg. 127.0.0.1
 * @param  string $range IP/CIDR netmask eg. 127.0.0.0/24, also 127.0.0.1 is accepted and /32 assumed
 * @return boolean true if the ip is in this range / false if not.
 */
function ip_in_range( $ip, $range ) {
	if ( strpos( $range, '/' ) == false ) {
		$range .= '/32';
	}
	// $range is in IP/CIDR format eg 127.0.0.1/24
	list( $range, $netmask ) = explode( '/', $range, 2 );
	$range_decimal = ip2long( $range );
	$ip_decimal = ip2long( $ip );
	$wildcard_decimal = pow( 2, ( 32 - $netmask ) ) - 1;
	$netmask_decimal = ~ $wildcard_decimal;
	return ( ( $ip_decimal & $netmask_decimal ) == ( $range_decimal & $netmask_decimal ) );
}

See also the implementation by cloudflare, supporting ipv4 and v6: https://github.com/cloudflare/CloudFlare-Tools/blob/master/cloudflare/ip_in_range.php

Thanks for the link! This is what I need.

Thanks a lot !

Thank you.. useful for a lot of projects

Thanks!

good stuff

how to find ipv6 in range.

Great Job.

this modification can be made
if (strpos($range, '/' ) == false) { return $ip == $range; }