How to Ping a Remote Server Port in PHP?

Pinging a Server Port with PHP

Getting the connectivity status of a remote server is a crucial aspect of network management and testing. PHP provides a simple means to ping an IP address and port using the fsockopen() function. However, the existing script mentioned in the question is limited to testing websites, not specific IP:port combinations.

To address this need, we can leverage the TCP connection establishment mechanism. By attempting to establish a TCP connection with a given IP address and port, we can infer the server's availability. The code below encapsulates this functionality:

<code class="php"><?php

function ping($host, $port, $timeout) 
{ 
  $tB = microtime(true); 
  $fP = fsockopen($host, $port, $errno, $errstr, $timeout); 
  if (!$fP) { return "down"; } 
  $tA = microtime(true); 
  return round((($tA - $tB) * 1000), 0)." ms"; 
}

// Usage example: ping a server at IP address 127.0.0.1, port 80
echo ping("127.0.0.1", 80, 10);

?></code>

This code snippet determines whether a server is accepting TCP connections on the specified port. If a connection is established within the given timeout, the function returns the ping response time in milliseconds; otherwise, it returns "down" to indicate that the server is unreachable.

To further refine the response, you can use the pingDomain() function provided in the accepted answer:

<code class="php"><?php

function pingDomain($domain){
    $starttime = microtime(true);
    $file      = fsockopen ($domain, 80, $errno, $errstr, 10);
    $stoptime  = microtime(true);
    $status    = 0;

    if (!$file) $status = -1;  // Site is down
    else {
        fclose($file);
        $status = ($stoptime - $starttime) * 1000;
        $status = floor($status);
    }
    return $status;
}

// Usage example: ping a server at domain name example.com
echo pingDomain("example.com");

?></code>

By leveraging PHP's socket functions, we can effectively ping both IP addresses and domain names to test connectivity and identify unresponsive hosts.

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