Use 0 for port to bind a random (free) port for incoming connections:
socket_bind ($socket, $bind_address, 0);
socket_getsockname($socket, $socket_address, $socket_port);
socket_listen($socket);
...
$socket_port contains the assigned port, you might want to send it to a remote client connecting. Tested with php 5.03.
socket_bind
(PHP 4 >= 4.0.7, PHP 5)
socket_bind — Binds a name to a socket
Description
Binds the name given in address to the socket described by socket . This has to be done before a connection is be established using socket_connect() or socket_listen().
Parameters
- socket
-
A valid socket resource created with socket_create().
- address
-
If the socket is of the AF_INET family, the address is an IP in dotted-quad notation (e.g. 127.0.0.1).
If the socket is of the AF_UNIX family, the address is the path of a Unix-domain socket (e.g. /tmp/my.sock).
- port (Optional)
-
The port parameter is only used when connecting to an AF_INET socket, and designates the port on the remote host to which a connection should be made.
Return Values
Returns TRUE on success or FALSE on failure.
The error code can be retrieved with socket_last_error(). This code may be passed to socket_strerror() to get a textual explanation of the error.
Examples
Example #1 Using socket_bind() to set the source address
<?php
// Create a new socket
$sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
// An example list of IP addresses owned by the computer
$sourceips['kevin'] = '127.0.0.1';
$sourceips['madcoder'] = '127.0.0.2';
// Bind the source address
socket_bind($sock, $sourceips['madcoder']);
// Connect to destination address
socket_connect($sock, '127.0.0.1', 80);
// Write
$request = 'GET / HTTP/1.1' . "\r\n" .
'Host: example.com' . "\r\n\r\n";
socket_write($sock, $request);
// Close
socket_close($sock);
?>
Notes
Note: This function must be used on the socket before socket_connect().
Note: Windows 9x/ME compatibility note: socket_last_error() may return an invalid error code if trying to bind the socket to a wrong address that does not belong to your machine.
socket_bind
13-Jun-2005 09:16
03-May-2003 09:19
The aforementioned tidbit about using NULL to bind to all addresses did not work for me, as I would receive an error about unknown address. Using a 0 worked for me:
socket_bind ($socket, 0, $port)
This also allows you to receive UDP broadcasts, which is what I had been trying to figure out.
13-Feb-2003 06:31
If you want to connect to server by specified port and you don't know your ip address or you have multiple interface for connecting to network, you can bind null instead of valid ip address like this :
<?php
$socket=socket_create(AF_INET,SOCK_STREAM,SOL_TCP);
$local_port=1023;
socket_bind($socket,null,$local_port);
socket_connect($socket,$remote_host,$remote_port);
?>
10-Jun-2002 02:22
If you want to reuse address and port, and get rid of error: unable to bind, address already in use, you have to use socket_setopt (check actual spelling for this function in you PHP verison) before calling bind:
<?php
if (!socket_set_option($sock, SOL_SOCKET, SO_REUSEADDR, 1)) {
echo socket_strerror(socket_last_error($sock));
exit;
}
?>
This solution was found by
Christophe Dirac. Thank you Christophe!
