PHP $_Server['Remote_Addr'] Shows Ipv6

PHP $_SERVER['REMOTE_ADDR'] shows IPv6

The server is then accepting connections on an IPv6 socket. Some operating systems can do both IPv4 and IPv6 on an IPv6 socket. When that happens the IPv6 address will look like ::ffff:192.0.2.123 or ::ffff:c000:027b which is the same address but written in hexadecimal.

If you see IPv6 addresses like 2a00:8640:1::224:36ff:feef:1d89 then your webserver really is reachable over IPv6 :-)

Anyway, to convert everything back to a canonical form you can use something like:

// Known prefix
$v4mapped_prefix_hex = '00000000000000000000ffff';
$v4mapped_prefix_bin = pack("H*", $v4mapped_prefix_hex);

// Or more readable when using PHP >= 5.4
# $v4mapped_prefix_bin = hex2bin($v4mapped_prefix_hex); 

// Parse
$addr = $_SERVER['REMOTE_ADDR'];
$addr_bin = inet_pton($addr);
if( $addr_bin === FALSE ) {
  // Unparsable? How did they connect?!?
  die('Invalid IP address');
}

// Check prefix
if( substr($addr_bin, 0, strlen($v4mapped_prefix_bin)) == $v4mapped_prefix_bin) {
  // Strip prefix
  $addr_bin = substr($addr_bin, strlen($v4mapped_prefix_bin));
}

// Convert back to printable address in canonical form
$addr = inet_ntop($addr_bin);

Using this code, when you input one of the following:

::ffff:192.000.002.123
::ffff:192.0.2.123
0000:0000:0000:0000:0000:ffff:c000:027b
::ffff:c000:027b
::ffff:c000:27b
192.000.002.123
192.0.2.123

you always get the canonical IPv4 address 192.0.2.123 as output.

And of course IPv6 addresses get returned as canonical IPv6 addresses: 2a00:8640:0001:0000:0224:36ff:feef:1d89 becomes 2a00:8640:1::224:36ff:feef:1d89 etc.

REMOTE_ADDR and IPv6 in PHP

The REMOTE_ADDR key is set by the web server, not PHP. If the web server listens on v6 and the user connects that way, it'll be a v6 address

IPV6 notation of $_SERVER['REMOTE_ADDR']

If you use inet_pton() first, and then convert it back to a string with inet_ntop() you should have a consistent string representation. I wouldn't rely on the input to be consistent...

How show IPv4 only with REMOTE_ADDR in PHP?

$_SERVER['REMOTE_ADDR'] always contains the address of the visitor. If it contains an IPv6 address then the visitor used IPv6 and there is no IPv4 address. And vice versa of course. These days you have to be able to deal with both.

Some visitors will have only IPv4, some will have only IPv6 and some will have both. The browser decides what is available and what it will use, and that's all you'll see. Note that a browser that has both might even switch between IPv4 and IPv6 between requests if it deems that necessary for good connectivity.

IP Address of the machine in PHP gives ::1 but why?

::1 is the actual IP. It is an ipv6 loopback address (i.e. localhost). If you were using ipv4 it would be 127.0.0.1.

If you want to get a different IP address, then you'll need to connect to the server through a different network interface.

$_SERVER['REMOTE_ADDR'] not giving the right ip address

<input type="hidden" name="ip" value="<?php echo $_SERVER['REMOTE_ADDR']; ?>" />

Don't do that. Get the request from $_SERVER when the form is submitted. Getting it when the form is generated and storing it in the form just gives people the opportunity to change it.

Does this IP address normally happen when I use it in a localhost (XAMPP)?

Yes. Getting the local IP (IPv6) address is normal when you request a page from localhost.

$_SERVER['REMOTE_ADDR'] is not returning ip address

::1 is the actual IP. It is an ipv6 address (i.e. localhost). If you were using ipv4 it would be 127.0.0.1.

If you want to get a different IP address, then you'll need to connect to the server through a different network interface.

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