PHP fsockopen() 失败未打开端口但 telnet 工作

Question

在过去 2 天里，我遇到了一个奇怪的网络问题，试图解决这个问题。我无法在 php 网页上打开端口 25003。该代码似乎没有问题，但是如下所示。

$host = 'xx.xx.xx.xx';    // statis public ip address assigned by my isp
$ports = array(80, 25003);

foreach ($ports as $port)
{
    $connection = fsockopen($host, $port);

    if (is_resource($connection))
    {
        echo '<h2>' . $host . ':' . $port . ' ' . '(' . getservbyport($port, 'tcp') . ') is open.</h2>' . "\n";

        fclose($connection);
    }

    else
    {
        echo '<h2>' . $host . ':' . $port . ' is not responding.</h2>' . "\n";
    }
}

端口 80 显示打开，但端口 25003 未显示。

该站点也托管在具有静态 IP 的 Bluehost 共享托管计划上。与他们交叉验证了 3 次以上，即端口 25003 在传入和传出连接上都是打开的。他们会撒谎吗，我不这么认为。

在客户端 PC 设置上：

(1) Firewall is disabled for testing purpose.

(2) Port forwarding is done correctly in router. I assume so because
 I can easily telnet MY PUBLIC IP with a port 25003 within the same
 LAN and from phone using sim card's internet.

(3) I did a port check from https://ping.eu/port-chk/ and it shows open.

(4) Client PC has a serproxy installed for serial to IP & Port.
(5) When I do a port check from above link, serproxy shows following message which seems to be okay on its part.
      * server thread launched
      * server(1) - thread started
      * server(1) - EOF from sock
      * server(1) - Exiting

(6) Again, when I telnet from external lan, it shows above message in Client PC's Serproxy which means it is doing its work properly. And it shows correct data from serial port to cmd line while telneting. 

问题是，当我使用上述代码片段打开 fsockopen 时，它显示 CONNECTION REFUSED。

下面是我的实际代码，它应该尝试从串行端口连接和读取数据，但连接被拒绝。

$fp = fsockopen("tcp://xx.xx.xx.xx", 25003, $errno, $errstr);
if (!$fp) {
    echo "$errstr ($errno)<br />\n";
} else {
    if (!feof($fp)) {
        $weight = trim(fgets($fp, 64)," ");
    }
}
echo $weight;
 fclose($fp);

我认为问题在于 bluehost 共享服务器或客户端 windows PC 或 SERPROXY 或本地网络配置。除了正确设置的 SERPROXY 中的波特率、com 端口等之外，恐怕还有任何重大的配置更改。

我现在完全不知道如何解决上述问题。如果有人可以提供帮助将不胜感激。

如果有人想检查连接，我会共享公共 IP。

Answer 1

就像我提到的 - 之前当我尝试连接时，所有尝试都失败了，但下面的两种方法现在都可以工作，所以我认为问题已经解决。我可能会建议重新启动网络服务器和浏览器

<?php
    set_time_limit( 0 );
    error_reporting( E_ALL );

    $address = 'xxx.xxx.xxx.xxx';
    $port = 25003;


    /* Method #1 */
    $fp = fsockopen( "tcp://{$address}", 25003, $errno, $errstr );
    if( !$fp ) echo "$errstr ($errno)<br />\n";
    else {
        if( !feof( $fp ) ) {
            $weight = trim(fgets($fp, 64)," ");
        }
    }
    printf('<h1>Method #1</h1>Weight: %s<br /><br />',$weight);
    fclose($fp);




    /* Method #2 */
    function geterror(){
        $obj=new stdClass;
        $obj->code=socket_last_error();
        $obj->error=socket_strerror( $obj->code );
        return $obj;
    }
    function negotiate( $socket ) {
        socket_recv( $socket, $buffer, 1024, 0 );

        for( $chr = 0; $chr < strlen( $buffer ); $chr++ ) {
            if( $buffer[ $chr ] == chr( 255 ) ) {
                $send = ( isset( $send ) ? $send . $buffer[$chr] : $buffer[$chr] );

                $chr++;
                if( in_array($buffer[$chr], array(chr(251), chr(252))) ) $send .= chr(254);
                if( in_array($buffer[$chr], array(chr(253), chr(254))) ) $send .= chr(252);

                $chr++;
                $send .= $buffer[$chr];
            } else {
                break;
            }
        }
        if( isset($send)) socket_send($socket, $send, strlen($send), 0);
        if( $chr - 1 < strlen($buffer)) return substr($buffer, $chr);
    }



    $socket = socket_create( AF_INET, SOCK_STREAM, SOL_TCP );


    try{

        if( $socket && is_resource( $socket ) ){
            if( !socket_connect( $socket, $address, $port ) ){
                $err=geterror();
                throw new Exception( sprintf( 'socket_connect: %s', $err->error ), $err->code );
            } else {

                while( true ){

                    $e=null;
                    $w=null;
                    $r = array( $socket );
                    $c = socket_select( $r, $w, $e, 5 );

                    foreach( $r as $read_socket ) {
                        if( $r = negotiate( $read_socket ) ) {
                            exit( sprintf( '<h1>Method #2</h1>Reading: %s', print_r( $r, true ) ) );
                        }
                    }
                }
            }

        } else {
            $err=geterror();
            throw new Exception( sprintf( 'Failed to create socket: %s',$err->error ), $err->code );
        }

    }catch( Exception $e ){
        printf( "
        <pre>
            <h1>Error: %d</h1>\nMessage: %s\nTrace: %s\nLine: %d
        </pre>",$e->getCode(),$e->getMessage(),$e->getTraceAsString(),$e->getLine() );
    }
    socket_close( $socket );
?>