How to code feature on checking visitor IP address in PHP ?

Question

i still confused on this subject And ask for any help and reference on how to check visitor IP address via PHP.

i'm know it seem lazy to ask something before attempt to code something to show. but right now, i also googling to find it. hopefully someone can give general broad answer or some link to read.

btw, what to be consider when we had to code some feature like this ?

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Thanks for everyone

ps: Thank you very much everybody. It's been an enlightening arguments. Frankly, i choose the answer more as respect rather then the true in it. Cause until now i still don't know the right one. maybe i need another years of learning before i got firm understanding of the topic itself.

Answer 1

If your client is surfing through a proxy server, then $_SERVER['REMOTE_ADDR'] just returns the IP address of the proxy server — not of the client’s machine. That’s not very reliable. This might be a better solution:

function get_ip_address() {
 foreach (array('HTTP_CLIENT_IP', 'HTTP_X_FORWARDED_FOR', 'HTTP_X_FORWARDED', 'HTTP_X_CLUSTER_CLIENT_IP', 'HTTP_FORWARDED_FOR', 'HTTP_FORWARDED', 'REMOTE_ADDR') as $key) {
  if (array_key_exists($key, $_SERVER)) {
   foreach (explode(',', $_SERVER[$key]) as $ip) {
    $ip = trim($ip); // just to be safe
    if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_IPV6 | FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) !== false) {
     self::$ip = $ip;
     return $ip;
    }
   }
  }
 }
}

This has already been discussed on Stack Overflow before. Please refer to “What is the most accurate way to retrieve a user’s correct IP address in PHP?”. The above code is an optimized version of the accepted answer to that question.

However, do note that getting IP addresses is never fully reliable: http://stackoverflow.com/questions/1672827/php-ajax-remote-addr-set-to-ip-of-bogus-network-adapter/1678748#1678748

Answer 2

See $_SERVER, specifically:

$_SERVER['REMOTE_ADDR'];

Answer 3

General broad answer: everything PHP knows about client is stored in the $_SERVER variable. So, do this code everytime you want particular info to see if you can find something relevant:

echo "<pre>";
print_r($_SERVER);
echo "</pre>";
//or just
phpinfo(32);

$_SERVER['REMOTE_ADDR'] is the only IP address you can get, though it can be not a "client address".

Answer 4

hi to get user ip you should use this

$ip=$_SERVER['REMOTE_ADDR']

Answer 5

$ip = $_SERVER['REMOTE_ADDR'];

echo "IP address is : " :.$ip;

this would serve the purpose

Answer 6

i suggest you use a third party ip to geo converter to calculate the location. since you wouldnt have to bare the db space.. acuracy and the queries.

all you will need to do is something like

http://third-party-url.com?ip=IP_ADDRESS

and it gives back an xml or an array of data.

u can use that to do what ever you want later on.

here are two websites which are popular. http://www.hostip.info/ http://simplegeo.com/

there are many such sites.. may be others can add them here

Answer 7

Ok, justjoe, I see you got confused with this arguement and there is my big part in it.

Some more explanations for you.

The answer depends on the task. You have 2 options:

If you need only one IP address, you can use only REMOTE_ADDR and nothing else. Take a look at the web-server's access log: there is only one IP address and it's REMOTE_ADDR one. At least it guaraneed you valid IP address. In many cases, like traffic counter, it's the only thing you can rely on. Thes is general answer to the "How to get an IP address" question.

If you want to record an address that can be more precise probably - so, noone forbids you from recording many addresses, not one. But of course, you have to record these HTTP headers along with REMOTE_ADDR, not instead of it. There is some use for such a throng of addresses. But you can't rely on it too much. But you can dig some info from it, if you care.

The only case for the FORWARDED_FOR header is misconfigured webserver, who place the real IP into this variable. In this case it can be used as an IP address. But of course it must be done manually, in the every particular case, not as the general recommendation. But anyway I'd quit such a webserver as it can be not only one misconfig in it.

Answer 8

just use this at the top of your code:

if(function_exists('apache_request_headers'))
{
    $headers = apache_request_headers();

    if(array_key_exists('X-Forwarded-For', $headers))
    {
        $ips = explode(',',$headers['X-Forwarded-For'],2);
        $_SERVER["REMOTE_ADDR"]= trim($ips[0]);
    } 
}

it will make sure that $_SERVER["REMOTE_ADDR"] always keep proper ip on load balancers apps or no.