Network Functions

checkdnsrr — Check DNS records corresponding to a given Internet host name or IP address
closelog — Close connection to system logger
dns_check_record — Alias of checkdnsrr
dns_get_mx — Alias of getmxrr
dns_get_record — Fetch DNS Resource Records associated with a hostname
fsockopen — Open Internet or Unix domain socket connection
gethostbyaddr — Get the Internet host name corresponding to a given IP address
gethostbyname — Get the IPv4 address corresponding to a given Internet host name
gethostbynamel — Get a list of IPv4 addresses corresponding to a given Internet host name
gethostname — Gets the host name
getmxrr — Get MX records corresponding to a given Internet host name
getprotobyname — Get protocol number associated with protocol name
getprotobynumber — Get protocol name associated with protocol number
getservbyname — Get port number associated with an Internet service and protocol
getservbyport — Get Internet service which corresponds to port and protocol
header — Send a raw HTTP header
header_register_callback — Call a header function
header_remove — Remove previously set headers
headers_list — Returns a list of response headers sent (or ready to send)
headers_sent — Checks if or where headers have been sent
http_clear_last_response_headers — Clears the stored HTTP response headers
http_get_last_response_headers — Retrieve last HTTP response headers
http_response_code — Get or Set the HTTP response code
inet_ntop — Converts a packed internet address to a human readable representation
inet_pton — Converts a human readable IP address to its packed in_addr representation
ip2long — Converts a string containing an (IPv4) Internet Protocol dotted address into a long integer
long2ip — Converts a long integer address into a string in (IPv4) Internet standard dotted format
net_get_interfaces — Get network interfaces
openlog — Open connection to system logger
pfsockopen — Open persistent Internet or Unix domain socket connection
setcookie — Send a cookie
setrawcookie — Send a cookie without urlencoding the cookie value
socket_get_status — Alias of stream_get_meta_data
socket_set_blocking — Alias of stream_set_blocking
socket_set_timeout — Alias of stream_set_timeout
syslog — Generate a system log message

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User Contributed Notes 10 notes

down

17 years ago

A simple and very fast function to check against CIDR.

Your previous examples are too complicated and involves a lot of functions call.

Here it is (only with arithmetic operators and call only to ip2long () and split() ):
<?php
  function ipCIDRCheck ($IP, $CIDR) {
    list ($net, $mask) = split ("/", $CIDR);
    
    $ip_net = ip2long ($net);
    $ip_mask = ~((1 << (32 - $mask)) - 1);

    $ip_ip = ip2long ($IP);

    $ip_ip_net = $ip_ip & $ip_mask;

    return ($ip_ip_net == $ip_net);
  }
?>
call example: <?php echo ipCheck ("192.168.1.23", "192.168.1.0/24"); ?>

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Anton Avramov - lukav at lukav dot com ¶

7 years ago

An improved version of claudiu at cnixs dot com not using split and working with the following: 
ip: 192.168.101.123, CIRD: 192.168.101.144/24 

<?php 
function ipCIDRCheck ($IP, $CIDR) {
    list ($net, $mask) = explode ('/', $CIDR);
    
    $ip_net = ip2long ($net);
    $ip_mask = ~((1 << (32 - $mask)) - 1);

    $ip_ip = ip2long ($IP);

    return (($ip_ip & $ip_mask) == ($ip_net & $ip_mask));
  }
?>

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Anonymous ¶

8 years ago

improved version of philippe-at-cyberabuse.org's answer:

<?php
function cidrconv($net) { 
    $start = strtok($net,"/"); 
    $n = 3 - substr_count($net, "."); 
    if ($n > 0)
    {
        for ($i = $n;$i > 0; $i--)
            $start .= ".0";
    } 
    $bits1 = str_pad(decbin(ip2long($start)), 32, "0", STR_PAD_LEFT);
    $net = (1 << (32 - substr(strstr($net, "/"), 1))) - 1; 
    $bits2 = str_pad(decbin($net), 32, "0", STR_PAD_LEFT); 
    $final = "";
    for ($i = 0; $i < 32; $i++)
    { 
        if ($bits1[$i] == $bits2[$i]) $final .= $bits1[$i]; 
        if ($bits1[$i] == 1 and $bits2[$i] == 0) $final .= $bits1[$i]; 
        if ($bits1[$i] == 0 and $bits2[$i] == 1) $final .= $bits2[$i]; 
    } 
    return array($start, long2ip(bindec($final))); 
}
?>

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David GASTALDIN ¶

17 years ago

Here a IP-Range to CIDRs function that I wrote for the purpose of filling my Postfix client.cidr with ripe-ncc data to block spamming from useless countries. Strcmp functions are meant to work around the silly PHP string comparison which inevitably tries compare strings as numbers when possible. I'll make no comment about that fact ... bit I have to bite my tong hard :

function PlageVersCIDRs($ip_min, $ip_max) {
    $cidrs = array();
    $ip_min_bin = sprintf('%032b', $ip_min);
    $ip_max_bin = sprintf('%032b', $ip_max);
    $ip_cour_bin = $ip_min_bin;
    while (strcmp($ip_cour_bin, $ip_max_bin) <= 0) {
        $lng_reseau = 32;
        $ip_reseau_bin = $ip_cour_bin;
        while (($ip_cour_bin[$lng_reseau - 1] == '0') && (strcmp(substr_replace($ip_reseau_bin, '1', $lng_reseau - 1, 1), $ip_max_bin) <= 0)) {
            $ip_reseau_bin[$lng_reseau - 1] = '1';
            $lng_reseau--;
        }
        $cidrs[] = long2ip(bindec($ip_cour_bin)).'/'.$lng_reseau;
        $ip_cour_bin = sprintf('%032b', bindec($ip_reseau_bin) + 1);
    }
    return $cidrs;
}

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philippe-at-cyberabuse.org ¶

22 years ago

PHP miss CIDR functions.



This one will convert a CIDR like this:

0.0.0.0/16 -> 0.0.0.0 - 0.0.255.255

127.0/16 -> 127.0.0.0 - 127.0.255.255

etc...



function cidrconv($net) {

$start=strtok($net,"/");

$n=3-substr_count($net, ".");

if ($n>0) { for ($i=$n;$i>0;$i--) $start.=".0"; }

$bits1=str_pad(decbin(ip2long($start)),32,"0","STR_PAD_LEFT");

$net=pow(2,(32-substr(strstr($net,"/"),1)))-1;

$bits2=str_pad(decbin($net),32,"0","STR_PAD_LEFT");

for ($i=0;$i<32;$i++) {

if ($bits1[$i]==$bits2[$i]) $final.=$bits1[$i];

if ($bits1[$i]==1 and $bits2[$i]==0) $final.=$bits1[$i];

if ($bits1[$i]==0 and $bits2[$i]==1) $final.=$bits2[$i];

}

return $start." - ".long2ip(bindec($final));

}

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-1

nexxer at rogers dot com ¶

19 years ago

In Trevor Hemsley's translation of the perl range2cidr function, the 

while ($end > $start) 

condition should be

while ($end >= $start)

otherwise it won't work for /32s, ie if you feed range2cidr("1.2.3.4", "1.2.3.4").

-- nex

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-2

-dR ¶

9 years ago

This little function might come in handy

<?php
function cidr_range( $cidr, $chkip=null )
{
    // Assign IP / mask
    list($ip,$mask) = explode("/",$cidr);

    // Sanitize IP
    $ip1 = preg_replace( '_(\d+\.\d+\.\d+\.\d+).*$_', '$1', "$ip.0.0.0" );

    // Calculate range
    $ip2 = long2ip( ip2long( $ip1 ) - 1 + ( 1 << ( 32 - $mask) ) );

    // are we cidr range cheking?
    if ( $chkip != null && ! filter_var( $chkip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) === false )
    {
        return ip2long( $ip1 ) <= ip2long( $chkip ) && ip2long( $ip2 ) >= ip2long( $chkip ) ? true : false;
    } else {
        return "$ip1 - $ip2";
    }
}

var_dump( cidr_range( "127.0/16", "127.0.0.1" ) );   // bool(true)
var_dump( cidr_range( "127.0/16", "192.168.0.1" ) ); // bool(false)
var_dump( cidr_range( "192.168.0.0/24" ) );          // string(27) "192.168.0.0 - 192.168.0.255"

?>

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-2

Anonymous ¶

21 years ago

Alternative cidr_conv function - a little easier to follow

function cidr_conv($cidr_address) {
  $first = substr($cidr_address, 0, strpos($cidr_address, "/"));
  $netmask = substr(strstr($cidr_address, "/"), 1);

  $first_bin = str_pad(decbin(ip2long($first)), 32, "0", STR_PAD_LEFT);
  $netmask_bin = str_pad(str_repeat("1", (integer)$netmask), 32, "0", STR_PAD_RIGHT);
  
  for ($i = 0; $i < 32; $i++) {
    if ($netmask_bin[$i] == "1") 
      $last_bin .= $first_bin[$i];
    else
      $last_bin .= "1";
  }

  $last = long2ip(bindec($last_bin));

  return "$first - $last";
}

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-4

samuele at norsam dot org ¶

20 years ago

To find if an IP is in a net/mask (very fast):
<?php
function isIPIn($ip,$net,$mask) {
   $lnet=ip2long($net);
   $lip=ip2long($ip);
   $binnet=str_pad( decbin($lnet),32,"0","STR_PAD_LEFT" );
   $firstpart=substr($binnet,0,$mask);
   $binip=str_pad( decbin($lip),32,"0","STR_PAD_LEFT" );
   $firstip=substr($binip,0,$mask);
   return(strcmp($firstpart,$firstip)==0);
   }
?>

This function can be compacted, avoiding some variable settings, but the function will not be too clear to read...
Example code, used to made a kind of location service network-based:

<?php
$n = array ( "192.168.0.0/16"   => "TUSCANY",
             "192.168.1.0/24"   => "- Florence",
             "192.168.2.0/24"   => "- Pisa",
             "192.168.3.0/24"   => "- Siena",
             "192.168.64.0/21" => "- Tuscan Archipelago",
             "192.168.64.0/23" => "--- Elba Island",
             "192.168.66.0/24" => "--- Capraia Island",
             "192.168.67.0/24" => "--- Giannutri Island");

// Normally you should use the following line
$myip = $HTTP_SERVER_VARS['REMOTE_ADDR'];
// This is first example: returns Tuscany/Pisa
$myip = "192.168.2.33";
// This is second example: returns Tuscany/T.Arch./Elba
$myip = "192.168.65.34";

echo "Your position:<br />\n";
foreach ( $n as $k=>$v ) {
   list($net,$mask)=split("/",$k);
   if (isIPIn($myip,$net,$mask)) {
       echo $n[$k]."<br />\n"; }
   }
?>

and so on...

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-5

dand at ddchosting.com ¶

18 years ago

When I was working on a project I ran into this problem with redirecting. My solution is as follows:

header("Refresh: 5; url=../main/main.php?".session_id()."");



This allowed me to pass the session_id() which is used throughout site to make sure user has loged in. 

I hope this helps!

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Network Functions

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