Socket context options

    Socket context options — Socket context option listing

    Description

    Socket context options are available for all wrappers that work over sockets, like tcp, http and ftp.

    Options

    bindto

    Used to specify the IP address (either IPv4 or IPv6) and/or the port number that PHP will use to access the network. The syntax is ip:port for IPv4 addresses, and [ip]:port for IPv6 addresses. Setting the IP or the port to 0 will let the system choose the IP and/or port.

    Note:

    As FTP creates two socket connections during normal operation, the port number cannot be specified using this option.

    backlog

    Used to limit the number of outstanding connections in the socket's listen queue.

    Note:

    This is only applicable to stream_socket_server().

    ipv6_v6only

    Overrides the OS default regarding mapping IPv4 into IPv6.

    Note:

    This is important in particular when trying to listen on IPv4 addresses separately while there exists a binding on [::].

    This is only applicable to stream_socket_server().

    so_reuseport

    Allows multiple bindings to a same ip:port pair, even from separate processes.

    Note:

    This is only applicable to stream_socket_server().

    so_broadcast

    Enables sending and receiving data to/from broadcast addresses.

    Note:

    This is only applicable to stream_socket_server().

    tcp_nodelay

    Setting this option to true will set SOL_TCP,NO_DELAY=1 appropriately, thus disabling the TCP Nagle algorithm.

    Changelog

    Version Description
    7.1.0 Added tcp_nodelay.
    7.0.1 Added ipv6_v6only.

    Examples

    Example #1 Basic bindto usage example

    <?php
    // connect to the internet using the '192.168.0.100' IP
    $opts = array(
    'socket' => array(
    'bindto' => '192.168.0.100:0',
    ),
    );


    // connect to the internet using the '192.168.0.100' IP and port '7000'
    $opts = array(
    'socket' => array(
    'bindto' => '192.168.0.100:7000',
    ),
    );


    // connect to the internet using the '2001:db8::1' IPv6 address
    // and port '7000'
    $opts = array(
    'socket' => array(
    'bindto' => '[2001:db8::1]:7000',
    ),
    );


    // connect to the internet using port '7000'
    $opts = array(
    'socket' => array(
    'bindto' => '0:7000',
    ),
    );


    // create the context...
    $context = stream_context_create($opts);

    // ...and use it to fetch the data
    echo file_get_contents('http://www.example.com', false, $context);

    ?>

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    User Contributed Notes 2 notes

    up
    10
    mix at ater dot me
    5 years ago
    The right way for forcing IPv6 is 'bindto' => '[::]:0'
    up
    2
    guru at jnt-finland dot fi
    9 years ago
    You can set "bindto" to "0:0" to force use IPv4 instead of IPv6. And probably "[0]:0" to force use IPv6, thou this I couldn't test.
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