PHP udp服务器：无法连接到远程主机

Question

I get this error message, when try connect to tiny UDP server. The source code is minimized and looks like so:

//server.php

$server_host = '127.0.0.1';
$server_port = 21665;
$poll_interval = 0.5;
$socket = socket_create(AF_INET, SOCK_DGRAM, 0);
socket_bind($socket, $server_host, $server_port);

$clients = [$socket];
while(true) {
    $read = $clients;
    $write = [];
    $except = [];

    if (socket_select($read, $write, $except, $poll_interval) < 1){
        continue;
    }

    if (in_array($socket, $read)) {
        echo "Client submitted request!
";
        //request parsing                   
    }                
}

So, when I run the server with $ php server.php it hangs for ever, as it should. When however I try to connect to it through telnet to post a request I get an error message:

$ telnet 127.0.0.1 21665
Trying 127.0.0.1 ...
Telnet: unable to connect to remote host: Connection refused

What I'm doing wrong and how can I fix it?

Answer 1

What I'm doing wrong

You are using telnet (a TCP client) to try to connect to a UDP port.

how can I fix it

Use a client that supports UDP, for example netcat as explained in this answer: telnet counterpart for udp

nc -u <host> <port>

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