PHP 소켓 서버에서 응답을받을 수 없습니다.

간단한 소켓 자바 클라이언트와 PHP CLI 기반 소켓 에코 서버를 만듭니다.
그러나 클라이언트는 서버에서 에코를 얻지 못합니다.
코드가 있습니다 ...

[CLIENT_CLASS (JAVA)]

import java.net.*;
import java.io.*;
import java.util.logging.Level;
import java.util.logging.Logger;

public class SocketManager
{

    public static void main(String args[])
    {
        int count = 0;
        Socket socket = null;
        System.out.println("[TO 8175] Connecting to " + "clashofages.ru" + ":" + 8175 + "...");
        while (socket == null) {
            if (count > 10) {
                System.out.println("[TO 8175] Can't connect to server...");
                return 1;
            }
            socket = connect("clashofages.ru", 8175);
            count++;
        }
        System.out.println("[TO 8175] Successfuly connected!");

        DataInputStream in = getInput(socket);
        if (in == null) {
            return 2;
        }
        DataOutputStream out = getOutput(socket);
        if (out == null) {
            return 3;
        }

        BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));
        String line = null;

        while (true) {
            System.out.println("[TO 8175] Type in message for server.");
            try {
                line = keyboard.readLine();
            } catch (IOException ex) {
                Logger.getLogger(SocketManager.class.getName()).log(Level.SEVERE, null, ex);
            }
            System.out.println("[TO 8175] Sending message to server...");
            int writeres = write(out, line);
            if (writeres != 2) {
                return 4 + writeres;
            }
            System.out.println("[TO 8175] Message sent successfuly!");
            if (line.equals("exit")) {
                System.out.println("[TO 8175] Exiting...");
                return 0;
            }
            line = read(in);
            if (line == null) {
                return 6;
            }
            System.out.println("[TO 8175] Server: " + line);
        }
    }

    public static Socket connect(String adress, int port)
    {
        Socket socket = null;
        InetAddress ipAddress = null;
        try {
            ipAddress = InetAddress.getByName(adress);
        } catch (UnknownHostException ex) {
            System.out.println("[SOCKET_ERROR] Can't convert " + adress + " to InetAdress object");
            return socket;
        }
        try {
            socket = new Socket(ipAddress, port);
        } catch (IOException ex) {
            System.out.println("[SOCKET_ERROR] Can't connect to " + adress + ":" + port);
            return null;
        }
        return socket;
    }

    public static DataInputStream getInput(Socket socket)
    {
        InputStream sin = null;
        try {
            sin = socket.getInputStream();
        } catch (IOException ex) {
            System.out.println("[SOCKET_ERROR] Can't get socket's input stream");
            return null;
        }
        return new DataInputStream(sin);
    }

    public static DataOutputStream getOutput(Socket socket)
    {
        OutputStream sout = null;
        try {
            sout = socket.getOutputStream();
        } catch (IOException ex) {
            System.out.println("[SOCKET_ERROR] Can't get socket's output stream");
            return null;
        }
        return new DataOutputStream(sout);
    }

    public static int write(DataOutputStream out, String string)
    {
        try {
            out.writeUTF(string);
        } catch (IOException ex) {
            System.out.println("[SOCKET_ERROR] Can't write to output stream");
            return 0;
        }
        try {
            out.flush();
        } catch (IOException ex) {
            System.out.println("[SOCKET_ERROR] Can't flush output stream");
            return 1;
        }
        return 2;
    }

    public static String read(DataInputStream in)
    {
        try {
            return in.readUTF();
        } catch (IOException ex) {
            System.out.println("[SOCKET_ERROR] Can't read input stream");
            return null;
        }
    }

[SERVER_CLI_CLASS (PHP)]

#!/usr/bin/php
<?php
error_reporting(E_ALL);
set_time_limit(0);
ob_implicit_flush();

$address = '0.0.0.0';
$port = 8175;

if (($sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) === false) {
    echo "[SERVER] socket_create() failed: ".socket_strerror(socket_last_error())."\n";
}
if (socket_bind($sock, $address, $port) === false) {
    echo "[SERVER] socket_bind() failed: ".socket_strerror(socket_last_error($sock))."\n";
}
if (socket_listen($sock, 5) === false) {
    echo "[SERVER] socket_listen() failed: ".socket_strerror(socket_last_error($sock))."\n";
}
echo "[SERVER] Start listening ".$address.":".$port."\n";
do {
    if (($msgsock = socket_accept($sock)) === false) {
        echo "[SERVER] socket_accept() failed: reason: ".socket_strerror(socket_last_error($sock))."\n";
        break;
    }
    echo "[SERVER] Client connected!\n";
    $msg = "[SERVER] Welcome!\n";
    socket_write($msgsock, $msg, strlen($msg));

    do {
        if (false === ($buf = socket_read($msgsock, 2048, PHP_NORMAL_READ))) {
            echo "[SERVER] socket_read() failed: ".socket_strerror(socket_last_error($msgsock))."\n";
            break 2;
        }
        if (!$buf = trim($buf)) {
            continue;
        }
        if ($buf == 'quit') {
            break;
        }
        $talkback = "[SERVER] You said '$buf'.\n";
        socket_write($msgsock, $talkback, strlen($talkback));
        echo "[CLIENT] $buf\n";
    } while (true);
    socket_close($msgsock);
} while (true);

socket_close($sock);
?>

서버 출력 :

[SERVER] Start listening 0.0.0.0:8175
[SERVER] Client connected!

클라이언트 출력 :

[TO 8175] Connecting to clashofages.ru:8175...
[TO 8175] Successfuly connected!
[TO 8175] Type in message for server.
Hi!
[TO 8175] Sending message to server...
[TO 8175] Message sent successfuly!

알 겠어요, 형제 님?

추신 : PHP가 클라이언트에 쓰려고 할 때 문제가 발생한다고 생각합니다.
PPS 직접 시도해 볼 수 있습니다. 서버가 작동 중입니다 ..