inet_ntop

    (PHP 5 >= 5.1.0, PHP 7, PHP 8)

    inet_ntop — Converts a packed internet address to a human readable representation

    Description

    inet_ntop(string $ip): string|false

    This function converts a 32bit IPv4, or 128bit IPv6 address (if PHP was built with IPv6 support enabled) into an address family appropriate string representation.

    Parameters

    ip

    A 32bit IPv4, or 128bit IPv6 address.

    Return Values

    Returns a string representation of the address or false on failure.

    Examples

    Example #1 inet_ntop() Example

    <?php
    $packed     = chr(127) . chr(0) . chr(0) . chr(1);
    $expanded = inet_ntop($packed);

    /* Outputs: 127.0.0.1 */
    echo $expanded;

    $packed = str_repeat(chr(0), 15) . chr(1);
    $expanded = inet_ntop($packed);

    /* Outputs: ::1 */
    echo $expanded;
    ?>

    See Also

    • long2ip() - Converts a long integer address into a string in (IPv4) Internet standard dotted format
    • ip2long() - Converts a string containing an (IPv4) Internet Protocol dotted address into a long integer
    • inet_pton() - Converts a human readable IP address to its packed in_addr representation

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    User Contributed Notes 3 notes

    up
    52
    ryansun81 at gmail dot com
    14 years ago
    For people who wondering what the meaning of this function name:
    pton: a presentation(printable) format address to network address
    ntop: a network address to presentation(printable) format address
    up
    5
    marcus at synchromedia dot co dot uk
    9 years ago
    PHP's inet_ntop function is not compatible with the binary representation used by MySQL's INET6_ATON function, assuming you are using the recommended method of storing both IPv4 and IPv6 addresses in a VARBINARY(16) field. You need to convert it like this:

    /**
    * Convert a MySQL binary v4 (4-byte) or v6 (16-byte) IP address to a printable string.
    * @param string $ip A binary string containing an IP address, as returned from MySQL's INET6_ATON function
    * @return string Empty if not valid.
    */
    function inet6_ntop($ip) {
    $l = strlen($ip);
    if ($l == 4 or $l == 16) {
    return inet_ntop(pack('A' . $l, $ip));
    }
    return '';
    }

    You don't need a function going the other way because MySQL's INET6_NTOA is already compatible with PHP's inet_pton function.
    up
    -1
    MagicalTux at FF dot st
    19 years ago
    For people who need this function but don't have it, I could write a function which should give almost the same result.

    <?php
    function my_inet_ntop($ip) {
    if (    strlen($ip)==4) {
    // ipv4
    list(,$ip)=unpack('N',$ip);
    $ip=long2ip($ip);
    } elseif(    strlen($ip)==16) {
    // ipv6
    $ip=bin2hex($ip);
    $ip=substr(chunk_split($ip,4,':'),0,-1);
    $ip=explode(':',$ip);
    $res='';
    foreach(    $ip as $seg) {
    while(    $seg{0}=='0') $seg=substr($seg,1);
    if (    $seg!='') {
    $res.=($res==''?'':':').$seg;
    } else {
    if (    strpos($res,'::')===false) {
    if (    substr($res,-1)==':') continue;
    $res.=':';
    continue;
    }
    $res.=($res==''?'':':').'0';
    }
    }
    $ip=$res;
    }
    return     $ip;
    }
    ?>

    I followed IPv6 reprenstation rules :
    - A series of "0"s in a 16bit block can by represented by "0".
    - A series of blocks containing only "0"s can be suppressed and represented by "::" (this can be done only once)

    (source : http://www.ipv6style.jp/en/faq/latest.shtml#2003022112 )

    Example:
    <?php
    $packed     = str_repeat(chr(0), 15) . chr(1);
    $expanded = my_inet_ntop($packed);

    /* Outputs: ::1 */
    echo $expanded;
    ?>

    I checked in CVS (2005-04-25) and didn't find the inet_ntop function (I really needed to handle IPv6) so I implemented it myself !
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