Find the start and end IP addresses of a network segment-PHP Tutorial-php.cn

Find the starting and ending IP addresses of a network segment
For example: network segment (192168.1.5/24), its subnet mask is divided according to 24:
11111111.11111111.11111111.00000000(255.255.255.0)
Explanation: The IP address is 32bits, In dividing the network segment, 24 means that there are 24 1s in the front and 8 0s in the back. The algorithm of the starting IP address is: the binary of 192.168.1.5 is ANDed with the binary of the subnet mask.
The algorithm for ending the IP address is: first invert the binary number of the subnet mask, and then perform an "OR" operation with the binary number of 192.168.1.5
In actual application, what is obtained is the network address and broadcast address, network address + 1 is the first host address, and the broadcast address -1 is the last host address.

{
$n = intval($n);
if($n<0||$n>32)
die('error submask');
return str_repeat("1", $n).str_repeat("0",32-$n);
}
function revBin($s)
{
$p=array('0','1',' 2');
$r=array('2','0','1');
return str_replace($p,$r,$s);
}
function startIp($str,$bSub )
{
$bIp = decbin($str);
$bIp = str_pad($bIp,8,"0",STR_PAD_LEFT);
$sIp = bindec($bIp & $bSub);
return $sIp;
}
function endIp($str,$bSub)
{
$bIp = decbin($str);
$bIp = str_pad($bIp,8,"0",STR_PAD_LEFT);
$eIp = bindec($bIp | revBin($bSub));
return $eIp;
}
$ip = array('192','168','1','5');//Set the IP address, which can be obtained from the form, This is just for demonstration
$mask = '24'; //Set the mask
$bSub = mask2bin($mask); //Convert the subnet mask to binary
$mask = array();
$mask[] = substr($bSub,"0",8); //Divide the subnet mask into segments every 8 bits
$mask[] = substr($bSub,"8",8);
$mask[] = substr ($bSub,"16",8);
$mask[] = substr($bSub,"24",8);

echo '

< ;td>

for ($i=0;$i<4;$i++)

{

echo bindec($mask[$i]);

if( $i!=3)

echo ".";

}

echo '

Mask:
Network address:	'; for ($i=0 ;$i<4;$i++) { echo startIp($ip[$i],$mask[$i]); if($i!=3) echo "."; } echo '
First available:	'; for ($i=0;$i< ;3;$i++) { echo startIp($ip[$i],$mask[$i]); echo "."; } $ip_4 = startIp($ip[3],$mask[ 3]); echo ++$ip_4; echo '
< font size="2">Last available:	'; for ($i=0;$i< ;3;$i++) { echo endIp($ip[$i],$mask[$i]); echo "."; } $ip_4 = endIp($ip[3],$mask[ 3]); echo --$ip_4; echo '
< font size="2">Broadcast address:	'; for ($i=0;$i< ;4;$i++) { echo endIp($ip[$i],$mask[$i]); if($i!=3) echo "."; } ?> Copy code

Related labels：

求一个网段的开始、结束IP地址

source：php.cn

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