无法获取ip地址 PHP获取准确的IP地址的方法

<span>// 获取IP地址</span>
function GetIP() {
    <span>if</span>(<span>getenv</span>(<span>'HTTP_CLIENT_IP'</span>) && strcasecmp(<span>getenv</span>(<span>'HTTP_CLIENT_IP'</span>), <span>'unknown'</span>)) {
        <span>$thisip</span> = <span>getenv</span>(<span>'HTTP_CLIENT_IP'</span>);
    } elseif(<span>getenv</span>(<span>'HTTP_X_FORWARDED_FOR'</span>) && strcasecmp(<span>getenv</span>(<span>'HTTP_X_FORWARDED_FOR'</span>), <span>'unknown'</span>)) {
        <span>$thisip</span> = <span>getenv</span>(<span>'HTTP_X_FORWARDED_FOR'</span>);
    } elseif(<span>getenv</span>(<span>'REMOTE_ADDR'</span>) && strcasecmp(<span>getenv</span>(<span>'REMOTE_ADDR'</span>), <span>'unknown'</span>)) {
        <span>$thisip</span> = <span>getenv</span>(<span>'REMOTE_ADDR'</span>);
    } elseif(isset(<span>$_SERVER</span>[<span>'REMOTE_ADDR'</span>]) && <span>$_SERVER</span>[<span>'REMOTE_ADDR'</span>] && strcasecmp(<span>$_SERVER</span>[<span>'REMOTE_ADDR'</span>], <span>'unknown'</span>)) {
        <span>$thisip</span> = <span>$_SERVER</span>[<span>'REMOTE_ADDR'</span>];
    }

    preg_match(<span>"/[\d\.]{7,15}/"</span>, <span>$thisip</span>, <span>$thisips</span>);
    <span>$thisip</span> = <span>$thisips</span>[<span>0</span>] ? <span>$thisips</span>[<span>0</span>] : <span>'unknown'</span>;
    <span>return</span><span>$thisip</span>;
}