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PHP : Function Reference : Socket Functions

Socket Functions


The socket extension implements a low-level interface to the socket communication functions based on the popular BSD sockets, providing the possibility to act as a socket server as well as a client.

For a more generic client-side socket interface, see stream_socket_client(), stream_socket_server(), fsockopen(), and pfsockopen().

When using these functions, it is important to remember that while many of them have identical names to their C counterparts, they often have different declarations. Please be sure to read the descriptions to avoid confusion.

Those unfamiliar with socket programming can find a lot of useful material in the appropriate Unix man pages, and there is a great deal of tutorial information on socket programming in C on the web, much of which can be applied, with slight modifications, to socket programming in PHP. The » Unix Socket FAQ might be a good start.


This extension has been moved to the » PECL repository and is no longer bundled with PHP as of PHP 5.3.0.


No external libraries are needed to build this extension.


The socket functions described here are part of an extension to PHP which must be enabled at compile time by giving the --enable-sockets option to configure.


IPv6 Support was added with PHP 5.0.0.

Runtime Configuration

This extension has no configuration directives defined in php.ini.

Resource Types

socket_accept(), socket_create_listen() and socket_create() return socket recources.

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

AF_UNIX (integer)
AF_INET (integer)
AF_INET6 (integer)
SOCK_STREAM (integer)
SOCK_DGRAM (integer)
SOCK_RAW (integer)
SOCK_RDM (integer)
MSG_OOB (integer)
MSG_WAITALL (integer)
MSG_PEEK (integer)
MSG_EOR (integer)
MSG_EOF (integer)
SO_DEBUG (integer)
SO_REUSEADDR (integer)
SO_KEEPALIVE (integer)
SO_DONTROUTE (integer)
SO_LINGER (integer)
SO_BROADCAST (integer)
SO_OOBINLINE (integer)
SO_SNDBUF (integer)
SO_RCVBUF (integer)
SO_SNDLOWAT (integer)
SO_RCVLOWAT (integer)
SO_SNDTIMEO (integer)
SO_RCVTIMEO (integer)
SO_TYPE (integer)
SO_ERROR (integer)
SOL_SOCKET (integer)
SOL_TCP (integer)
SOL_UDP (integer)

Socket Errors

The socket extension was written to provide a usable interface to the powerful BSD sockets. Care has been taken that the functions work equally well on Win32 and Unix implementations. Almost all of the sockets functions may fail under certain conditions and therefore emit an E_WARNING message describing the error. Sometimes this doesn't happen to the desire of the developer. For example the function socket_read() may suddenly emit an E_WARNING message because the connection broke unexpectedly. It's common to suppress the warning with the @-operator and catch the error code within the application with the socket_last_error() function. You may call the socket_strerror() function with this error code to retrieve a string describing the error. See their description for more information.


The E_WARNING messages generated by the socket extension are in English though the retrieved error message will appear depending on the current locale (LC_MESSAGES):

Warning - socket_bind() unable to bind address [98]: Die Adresse wird bereits verwendet ?>


Example 2289. Socket example: Simple TCP/IP server

This example shows a simple talkback server. Change the address and port variables to suit your setup and execute. You may then connect to the server with a command similar to: telnet 10000 (where the address and port match your setup). Anything you type will then be output on the server side, and echoed back to you. To disconnect, enter 'quit'.

#!/usr/local/bin/php -q

/* Allow the script to hang around waiting for connections. */

/* Turn on implicit output flushing so we see what we're getting
* as it comes in. */

$address = '';
$port = 10000;

if ((
$sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) === false) {
"socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";

if (
socket_bind($sock, $address, $port) === false) {
"socket_bind() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";

if (
socket_listen($sock, 5) === false) {
"socket_listen() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";

do {
   if ((
$msgsock = socket_accept($sock)) === false) {
"socket_accept() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
/* Send instructions. */
$msg = "\nWelcome to the PHP Test Server. \n" .
"To quit, type 'quit'. To shut down the server type 'shutdown'.\n";
socket_write($msgsock, $msg, strlen($msg));

   do {
       if (
false === ($buf = socket_read($msgsock, 2048, PHP_NORMAL_READ))) {
"socket_read() failed: reason: " . socket_strerror(socket_last_error($msgsock)) . "\n";
       if (!
$buf = trim($buf)) {
       if (
$buf == 'quit') {
       if (
$buf == 'shutdown') {
$talkback = "PHP: You said '$buf'.\n";
socket_write($msgsock, $talkback, strlen($talkback));
   } while (
} while (


Example 2290. Socket example: Simple TCP/IP client

This example shows a simple, one-shot HTTP client. It simply connects to a page, submits a HEAD request, echoes the reply, and exits.


"<h2>TCP/IP Connection</h2>\n";

/* Get the port for the WWW service. */
$service_port = getservbyname('www', 'tcp');

/* Get the IP address for the target host. */
$address = gethostbyname('');

/* Create a TCP/IP socket. */
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if (
$socket === false) {
"socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";
} else {

"Attempting to connect to '$address' on port '$service_port'...";
$result = socket_connect($socket, $address, $service_port);
if (
$result === false) {
"socket_connect() failed.\nReason: ($result) " . socket_strerror(socket_last_error($socket)) . "\n";
} else {

$in = "HEAD / HTTP/1.1\r\n";
$in .= "Host:\r\n";
$in .= "Connection: Close\r\n\r\n";
$out = '';

"Sending HTTP HEAD request...";
socket_write($socket, $in, strlen($in));

"Reading response:\n\n";
while (
$out = socket_read($socket, 2048)) {

"Closing socket...";

Table of Contents

socket_accept — Accepts a connection on a socket
socket_bind — Binds a name to a socket
socket_clear_error — Clears the error on the socket or the last error code
socket_close — Closes a socket resource
socket_connect — Initiates a connection on a socket
socket_create_listen — Opens a socket on port to accept connections
socket_create_pair — Creates a pair of indistinguishable sockets and stores them in an array
socket_create — Create a socket (endpoint for communication)
socket_get_option — Gets socket options for the socket
socket_getpeername — Queries the remote side of the given socket which may either result in host/port or in a Unix filesystem path, dependent on its type
socket_getsockname — Queries the local side of the given socket which may either result in host/port or in a Unix filesystem path, dependent on its type
socket_last_error — Returns the last error on the socket
socket_listen — Listens for a connection on a socket
socket_read — Reads a maximum of length bytes from a socket
socket_recv — Receives data from a connected socket
socket_recvfrom — Receives data from a socket whether or not it is connection-oriented
socket_select — Runs the select() system call on the given arrays of sockets with a specified timeout
socket_send — Sends data to a connected socket
socket_sendto — Sends a message to a socket, whether it is connected or not
socket_set_block — Sets blocking mode on a socket resource
socket_set_nonblock — Sets nonblocking mode for file descriptor fd
socket_set_option — Sets socket options for the socket
socket_shutdown — Shuts down a socket for receiving, sending, or both
socket_strerror — Return a string describing a socket error
socket_write — Write to a socket

Code Examples / Notes » ref.sockets


Wake on Lan , working ok without configurations, and some features
function wake_on_lan($mac,$addr=false,$port=7) {
//    $addr:
// You will send and broadcast tho this addres.
// Normaly you need to use the adres, so i made it as default. So you don't need
// to do anything with this.
// Since have permission denied problems you can use addr=false to get all broadcast address from ifconfig command
// addr can be array with broadcast IP values
//    $mac:
// You will WAKE-UP this WOL-enabled computer, you need to add the MAC-addres here.
// Mac can be array too
//    TRUE:    When socked was created succesvolly and the message has been send.
//    FALSE:    Something went wrong
//Example 1
//    When the message has been send you will see the message "Done...."
//    if ( wake_on_lan('00:00:00:00:00:00'))
//        echo 'Done...';
//    else
//        echo 'Error while sending';
if ($addr===false){
exec("ifconfig | grep Bcast | cut -d \":\" -f 3 | cut -d \" \" -f 1",$addr);
for ($i=0;$i<count($ret);$i++)
if ($ret[$i]!==false)
if (is_array($mac)){
foreach($mac as $k=>v)
//Check if it's an real MAC-addres and split it into an array
if (!preg_match("/([A-F0-9]{1,2}[-:]){5}[A-F0-9]{1,2}/",$mac,$maccheck))
return false;
$addr_byte = preg_split("/[-:]/",$maccheck[0]);
//Creating hardware adress
$hw_addr = '';
for ($a=0; $a < 6; $a++)//Changing mac adres from HEXEDECIMAL to DECIMAL
$hw_addr .= chr(hexdec($addr_byte[$a]));

//Create package data
$msg = str_repeat(chr(255),6);
for ($a = 1; $a <= 16; $a++)
$msg .= $hw_addr;
//Sending data
if (function_exists('socket_create')){
//socket_create exists
$sock = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP); //Can create the socket
if ($sock){
$sock_data = socket_set_option($sock, SOL_SOCKET, SO_BROADCAST, 1); //Set
if ($sock_data){
$sock_data = socket_sendto($sock, $msg, strlen($msg), 0, $addr,$port); //Send data
if ($sock_data){
socket_close($sock); //Close socket
$sock=fsockopen("udp://" . $addr, $port);

m dot hoppe

Very good step-by-step tutorial for a network daemon is here: [next]
[before] /psecom,id,484,nodeid,114.html
Sorry, I was forced to split this link. :-(


This function to send Magic Packet works really !!!
function wake($ip, $mac, $port)
 $nic = fsockopen("udp://" . $ip, $port);
   $packet = "";
   for($i = 0; $i < 6; $i++)
      $packet .= chr(0xFF);
   for($j = 0; $j < 16; $j++)
     for($k = 0; $k < 6; $k++)
       $str = substr($mac, $k * 2, 2);
       $dec = hexdec($str);
       $packet .= chr($dec);
   $ret = fwrite($nic, $packet);
     return true;
 return false;
Executed with:
wake('', '112233445566', 9);


There is a fantastic book on this library called 'TCP/IP Sockets in C' (ISBN 1558608265), that covers all of the ins and outs, quirks, and everything else that goes on. It's written for C, of course, but it could have easily been written for PHP with almost no serious code differences.


If you want to use any complicated preexisting protocols, you may find the function pack ( useful.


I've been using the ICMP Checksum calculation function written by Khaless [at] bigpond [dot] com. But when having an odd length of data, it failed, so I made my own instead, which adds a 0 if the data length is odd:
function icmpChecksum($data)
   // Add a 0 to the end of the data, if it's an "odd length"
   if (strlen($data)%2)
       $data .= "\x00";
   // Let PHP do all the dirty work
   $bit = unpack('n*', $data);
   $sum = array_sum($bit);
   // Stolen from: Khaless [at] bigpond [dot] com
   // The code from the original ping program:
   //    sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
   //    sum += (sum >> 16); /* add carry */
   // which also works fine, but it seems to me that
   // Khaless will work on large data.
   while ($sum>>16)
       $sum = ($sum >> 16) + ($sum & 0xffff);
   return pack('n*', ~$sum);


I spent a while trying to use SOCK_RAW to send ICMP request packets so i could ping. This however lead me to need the internet checksum written as a php function, which was a little hard because of the way PHP handles variable types. Anyway, to save others the effort heres what i came up with, this returns Checksum for $data
// Computes Internet Checksum for $data
// will return a 16-bit internet checksum for $data
function inetChecksum($data)
// 32-bit accumilator, 16 bits at a time, adds odd bit on at end
for($i=0;$i<strlen($data);$i += 2)
if($data[$i+1]) $bits = unpack('n*',$data[$i].$data[$i+1]);
else $bits = unpack('C*',$data[$i]);
$sum += $bits[1];

// Fold 32-bit sum to 16 bits
while ($sum>>16) $sum = ($sum & 0xffff) + ($sum >> 16);
$checksum = pack('n1',~$sum);
return $checksum;
And with this i was able to construct a correct PING Request.


I have spent the past two days ripping out hair trying to figure out how to prevent zombie processes w/the examples above and I just happend to find this in the manual for another lanuage, felt it neccassry to port it here.
--begin copy--
11-Oct-2002 02:53

Forking your PHP daemon will cause it to zombie on exit.
...or so I've seen on:
FreeBSD (PHP4.2.x)
Debian (PHP4.3.0-dev)
Darwin (PHP4.3.0-dev)
This was tested with the example code above and other scripts created for evaluation.
Seems adding <b>--enable-sigchild</b> to your configure will get rid of the problem.
Hope that saves some hair tearing :]
--end copy--
Thanks !!!!


I have searched long and hard for a ping script that does NOT use EXEC() or SYSTEM(). So far, I have found nothing, so I decided to write my own, which was a task to say the least.
First off, I would like to thank Khaless for their checksum function, converting it from C looked like a task in itself.
Here is the class I wrote
class Net_Ping
 var $icmp_socket;
 var $request;
 var $request_len;
 var $reply;
 var $errstr;
 var $time;
 var $timer_start_time;
 function Net_Ping()
   $this->icmp_socket = socket_create(AF_INET, SOCK_RAW, 1);
 function ip_checksum($data)
    for($i=0;$i<strlen($data);$i += 2)
        if($data[$i+1]) $bits = unpack('n*',$data[$i].$data[$i+1]);
        else $bits = unpack('C*',$data[$i]);
        $sum += $bits[1];
    while ($sum>>16) $sum = ($sum & 0xffff) + ($sum >> 16);
    $checksum = pack('n1',~$sum);
    return $checksum;
 function start_time()
   $this->timer_start_time = microtime();
 function get_time($acc=2)
   // format start time
   $start_time = explode (" ", $this->timer_start_time);
   $start_time = $start_time[1] + $start_time[0];
   // get and format end time
   $end_time = explode (" ", microtime());
   $end_time = $end_time[1] + $end_time[0];
   return number_format ($end_time - $start_time, $acc);
 function Build_Packet()
   $data = "abcdefghijklmnopqrstuvwabcdefghi"; // the actual test data
   $type = "\x08"; // 8 echo message; 0 echo reply message
   $code = "\x00"; // always 0 for this program
   $chksm = "\x00\x00"; // generate checksum for icmp request
   $id = "\x00\x00"; // we will have to work with this later
   $sqn = "\x00\x00"; // we will have to work with this later
   // now we need to change the checksum to the real checksum
   $chksm = $this->ip_checksum($type.$code.$chksm.$id.$sqn.$data);
   // now lets build the actual icmp packet
   $this->request = $type.$code.$chksm.$id.$sqn.$data;
   $this->request_len = strlen($this->request);
 function Ping($dst_addr,$timeout=5,$percision=3)
   // lets catch dumb people
   if ((int)$timeout <= 0) $timeout=5;
   if ((int)$percision <= 0) $percision=3;
   // set the timeout
     SOL_SOCKET,  // socket level
     SO_RCVTIMEO, // timeout option
      "sec"=>$timeout, // Timeout in seconds
      "usec"=>0  // I assume timeout in microseconds
   if ($dst_addr)
     if (@socket_connect($this->icmp_socket, $dst_addr, NULL))
     } else {
       $this->errstr = "Cannot connect to $dst_addr";
       return FALSE;
     socket_write($this->icmp_socket, $this->request, $this->request_len);
     if (@socket_recv($this->icmp_socket, &$this->reply, 256, 0))
       $this->time = $this->get_time($percision);
       return $this->time;
     } else {
       $this->errstr = "Timed out";
       return FALSE;
   } else {
     $this->errstr = "Destination address not specified";
     return FALSE;
$ping = new Net_Ping;
if ($ping->time)
 echo "Time: ".$ping->time;
 echo $ping->errstr;
Hope this saves some troubles.


I found this EXTREMELY useful link on the zend php
mailing list:
It's about being able to use multiple connections
in a php socket server, WITHOUT having
to use those threads everyone seems to be
so very fond of.
works very well :)
(ps: i didn't make it, so....don't say thanks to me ;),
thank him)


hexdump() is a fantastic function for "dumping" packets or binary output from servers. See the below link for more information.


Here is a good article on some of the differences between HTTP 1.0 and HTTP 1.1.


Here another socketclass which can handle the most importand things.
Here a little Chatserver based on this class.
Maybe its helpful :)


Function to send Magic Packets for Wake on Wan (WOW) or Wake on Lan(WOL), without sockets library.
function WakeOnLan($ip, $mac, $port)
   $packet = "";
       for($i = 0; $i < 6; $i++) $packet .= chr(0xFF);
       for($i = 0; $i < 6; $i++) $packet .= chr((int)substr($mac, $i, $i + 2));
$nic = fsockopen("udp://" . $ip, $port));
return false;
fwrite($nic, $packet);
return true;


For an implementation of a Socket Daemon framework that can handle both client and server sockets, async (non blocking) communication, which is flexible and easy to use see:


Below is a simple forked daemon I wrote in PHP. I haven't seen one yet anywhere else, so I thought some people might be wondering how to do  it. Execute
with php -q <file>
PHP forked daemon
Standalone PHP binary must be compiled with --enable-sockets and --enable-pcntl
Dave M. -2002
       Online Services USA
function sig_handler($signo) {
    switch($signo) {
        case SIGTERM:
            // handle shutdown tasks
        case SIGHUP:
            // handle restart tasks
        case SIGUSR1:
            print "Caught SIGUSR1...\n";
        case SIGCHLD:
        while( pcntl_waitpid(-1,$status,WNOHANG)>0 ) {
        case SIGINT:
            // not implemented yet...
function interact($sock) {
// Custom code goes here... e.g: socket_read() socket_write()...
function become_daemon() {
$child = pcntl_fork();
if($child) {
exit; // kill parent
posix_setsid(); // become session leader
umask(0); // clear umask
return posix_getpid();
function open_pid_file($file) {
if(file_exists($file)) {
$fp = fopen($file,"r");
$pid = fgets($fp,1024);
if(posix_kill($pid,0)) {
print "Server already running with PID: $pid\n";
print "Removing PID file for defunct server process $pid\n";
if(!unlink($file)) {
print "Cannot unlink PID file $file\n";
if($fp = fopen($file,"w")) {
return $fp;
} else {
print "Unable to open PID file $file for writing...\n";
function change_identity($uid,$gid) {
global $pid_file;
if(!posix_setgid($gid)) {
print "Unable to setgid to $gid!\n";
if(!posix_setuid($uid)) {
print "Unable to setuid to $uid!\n";

error_reporting (4);
set_time_limit (0);
ob_implicit_flush ();
$pid_file = '/tmp/';
$underpriv_uid = '99'; // uid 99 == user nobody, at least on my system.
$underpriv_gid = '99';
$port = 10000;
$address = 0; // 0 binds to all addresses, may not work on fbsd
$quit = 0;
pcntl_signal(SIGCHLD, "sig_handler");
pcntl_signal(SIGTERM, "sig_handler");
pcntl_signal(SIGINT, "sig_handler");
$fh = open_pid_file($pid_file);
if (($sock = socket_create (AF_INET, SOCK_STREAM, 0)) < 0) {
   print "socket_create() failed: reason: " . socket_strerror ($sock) . "\n";
if (($ret = socket_bind ($sock, $address, $port)) < 0) {
   print "socket_bind() failed: reason: " . socket_strerror ($ret) . "\n";
if (($ret = socket_listen ($sock, 0)) < 0) {
   print "socket_listen() failed: reason: " . socket_strerror ($ret) . "\n";
print "Server ready. Waiting for connections.....\n";
$pid = become_daemon();
while(!$quit) {
if (($connection = socket_accept($sock)) < 0) {

if( ($child = pcntl_fork()) == -1 ) {
print  "Could not fork!!\n";
print "Dying...\n";
elseif($child == 0) {


if(posix_getpid() == $pid) {


At the moment (2007-09), i don't find this extension in the PECL, but instead in the usual php extension directory. It needs to be included in the php-ini:
extension = php_sockets.dll
(or ".so" - whatever for your system).


After several hours of working with sockets in an attempt to do UDP broadcasting, I thought a little help was in order for anyone else looking to do something similar, since it uses a number of those "undocumented" functions.  Here's how I did it:
// here is a basic opening of the a socket.  AF_INET specifies the internet domain.  SOCK_DGRAM
// specifies the Datagram socket type the 0 specifies that I want to use the default protcol (which in this
// case is UDP)
$sock = socket(AF_INET, SOCK_DGRAM, 0);
// if the file handle assigned to socket is less than 0 then opening the socket failed
if($sock < 0)
echo "socket() failed, error: " . strerror($sock) . "\n";
// here's where I set the socket options, this is essential to allow broadcasting.  An earlier comment (as of
// June 4th, 2001) explains what the parameters are.  For my purposes (UDP broadcasting) I need to set
// the broadcast option at the socket level to true.  In C, this done using SOL_SOCKET as the level param
// (2) and SO_BROADCAST as the type param (3).  These may exist in PHP but I couldn't reference them  
// so I used the values that referencing these variables in C returns (namely 1 and 6 respectively).  This
// function is basically just a wrapper to the C  function so check out the C documentation for more info
$opt_ret = setsockopt($sock, 1, 6, TRUE);
// if the return value is less than one, an error occured setting the options
if($opt_ret < 0)
echo "setsockopt() failed, error: " . strerror($opt_ret) . "\n";
// finally I am ready to broad cast something.  The sendto function allows this without any
// connections (essential for broadcasting).  So, this function sends the contents of $broadcast_string to the
// general broadcast address ( on port 4096.  The 0 (param 4) specifies no special
// options, you can read about the options with man sendto
$send_ret = sendto($sock, $broadcast_string, strlen($broadcast_string), 0, '', 4096);
// if the return value is less than 0, an error has occured
if($send_ret < 0)
echo "sendto() failed, error: " . strerror($send_ret) . "
\n"; }
// be sure to close your socket when you're done


A simple HTTP request class using socket.
class HttpRequest
var $sHostAdd;
var $sUri;
var $iPort;

var $sRequestHeader;

var $sResponse;

function HttpRequest($sUrl)
$sPatternUrlPart = '/http:\/\/([a-z-\.0-9]+)(:(\d+)){0,1}(.*)/i';
$arMatchUrlPart = array();
preg_match($sPatternUrlPart, $sUrl, $arMatchUrlPart);

$this->sHostAdd = gethostbyname($arMatchUrlPart[1]);
if (empty($arMatchUrlPart[4]))
$this->sUri = '/';
$this->sUri = $arMatchUrlPart[4];
if (empty($arMatchUrlPart[3]))
$this->iPort = 80;
$this->iPort = $arMatchUrlPart[3];

$this->addRequestHeader('Host: '.$arMatchUrlPart[1]);
$this->addRequestHeader('Connection: Close');

function addRequestHeader($sHeader)
$this->sRequestHeader .= trim($sHeader)."\r\n";

function sendRequest($sMethod = 'GET', $sPostData = '')
$sRequest = $sMethod." ".$this->sUri." HTTP/1.1\r\n";
$sRequest .= $this->sRequestHeader;
if ($sMethod == 'POST')
$sRequest .= "Content-Type: application/x-www-form-urlencoded\r\n";
$sRequest .= "Content-Length: ".strlen($sPostData)."\r\n";
$sRequest .= "\r\n";
$sRequest .= $sPostData."\r\n";
$sRequest .= "\r\n";

$sockHttp = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if (!$sockHttp)
die('socket_create() failed!');

$resSockHttp = socket_connect($sockHttp, $this->sHostAdd, $this->iPort);
if (!$resSockHttp)
die('socket_connect() failed!');

socket_write($sockHttp, $sRequest, strlen($sRequest));

$this->sResponse = '';
while ($sRead = socket_read($sockHttp, 4096))
$this->sResponse .= $sRead;


function getResponse()
return $this->sResponse;

function getResponseBody()
$sPatternSeperate = '/\r\n\r\n/';
$arMatchResponsePart = preg_split($sPatternSeperate, $this->sResponse, 2);
return $arMatchResponsePart[1];


A multicast server can be written badly as follows:
$bc_string = "Hello World!";
$sock = socket_create(AF_INET, SOCK_DGRAM, 0);
$opt_ret = socket_set_option($sock, 1, 6, TRUE);
$send_ret = socket_sendto($sock, $bc_string, strlen($bc_string), 0, '', 4446);
Checking the return types is needed, but this does allow for you to multicast from php code.


A little example that shows how to implement a simple multi-client iterative server (without forking). Launch the server and connect multiple telnet clients on it. It's a basic chat program.
#!/usr/bin/php -q
$address = '';
$port = 8888;
function handle_client($allclient, $socket, $buf, $bytes) {
foreach($allclient as $client) {
socket_write($client, "$socket wrote: $buf");
if (($master = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) < 0) {
echo "socket_create() failed: reason: " . socket_strerror($master) . "\n";
socket_set_option($master, SOL_SOCKET,SO_REUSEADDR, 1);
if (($ret = socket_bind($master, $address, $port)) < 0) {
echo "socket_bind() failed: reason: " . socket_strerror($ret) . "\n";
if (($ret = socket_listen($master, 5)) < 0) {
echo "socket_listen() failed: reason: " . socket_strerror($ret) . "\n";
$read_sockets = array($master);
while (true) {
$changed_sockets = $read_sockets;
$num_changed_sockets = socket_select($changed_sockets, $write = NULL, $except = NULL, NULL);
foreach($changed_sockets as $socket) {
if ($socket == $master) {
if (($client = socket_accept($master)) < 0) {
echo "socket_accept() failed: reason: " . socket_strerror($msgsock) . "\n";
} else {
array_push($read_sockets, $client);
} else {
$bytes = socket_recv($socket, $buffer, 2048, 0);
if ($bytes == 0) {
$index = array_search($socket, $read_sockets);
} else {
$allclients = $read_sockets;
array_shift($allclients); // remove master
handle_client($allclients, $socket, $buffer, $bytes);



>The function, that send the WakeOnLan (WOL, Magic packet) signal:
# Wake on LAN - (c) HotKey (at SPR dot AT), upgraded by Murzik <>
function WakeOnLan($addr, $mac)
$addr_byte = explode(':', $mac);
$hw_addr = '';
for ($a=0; $a < 6; $a++) $hw_addr .= chr(hexdec($addr_byte[$a]));
$msg = chr(255).chr(255).chr(255).chr(255).chr(255).chr(255);
for ($a = 1; $a <= 16; $a++)    $msg .= $hw_addr;
// send it to the broadcast address using UDP
// SQL_BROADCAST option isn't help!!
$s = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
if ($s == false)
 echo "Error creating socket!\n";
 echo "Error code is '".socket_last_error($s)."' - " . socket_strerror(socket_last_error($s));
// setting a broadcast option to socket:
 $opt_ret =  socket_set_option($s, 1, 6, TRUE);
 if($opt_ret < 0)
  echo "setsockopt() failed, error: " . strerror($opt_ret) . "\n";
 $e = socket_sendto($s, $msg, strlen($msg), 0, $addr, 2050);
 echo "Magic Packet sent (".$e.") to ".$addr.", MAC=".$mac;
#WakeOnLan('', 'your:MAC:address');
#WakeOnLan('', '00:30:84:2A:90:42');
#WakeOnLan('', '00:05:1C:10:04:05');
//if you have switch or other routing devices in LAN, sendign to
// the local IP isn't helps! you need send to the broadcast address like this:
WakeOnLan('', '00:05:1C:10:04:05');


"Beej's Guide to Network Programming" is an absolutely excellent and easy to understand tutorial to socket programming. It was written for C developers, but as the socket functions in PHP are (almost) analoguous, this should not be a problem.

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