PHP : Static function not returning right value

Question

I have function of getting IP address, if I manually put the function under my PHP page its working. But I want to put it inside of a class as static function however, instead of giving the IP value it return ::1

audit.class

public static function get_client_ip() {
        $ipaddress = '';
        if (getenv('HTTP_CLIENT_IP'))
            $ipaddress = getenv('HTTP_CLIENT_IP');
        else if(getenv('HTTP_X_FORWARDED_FOR'))
            $ipaddress = getenv('HTTP_X_FORWARDED_FOR');
        else if(getenv('HTTP_X_FORWARDED'))
            $ipaddress = getenv('HTTP_X_FORWARDED');
        else if(getenv('HTTP_FORWARDED_FOR'))
            $ipaddress = getenv('HTTP_FORWARDED_FOR');
        else if(getenv('HTTP_FORWARDED'))
           $ipaddress = getenv('HTTP_FORWARDED');
        else if(getenv('REMOTE_ADDR'))
            $ipaddress = getenv('REMOTE_ADDR');
        else
            $ipaddress = 'UNKNOWN';
        return $ipaddress;
    }

.php

echo Audit::get_client_ip();
//result is ::1
//instead of ip******