Get real IP address and IP address verification functions in PHP

This article introduces two functions one is to verify the IP address, the other is to obtain the user's real IP address of the function, is also commonly used two IP operation function, the need for students can refer to.

1. Get the user's real IP address

function get_client_ip () {if (getenv ("REMOTE_ADDR") && STRCASECM                 P (getenv ("REMOTE_ADDR"), "Unknown")) {$onlineip = getenv ("REMOTE_ADDR");         return $ONLINEIP; } if (Isset ($_server[' remote_addr ')) && $_server[' remote_addr '] && strcasecmp ($_server[' REMOTE                 _addr '], "unknown") {$onlineip = $_server[' remote_addr '];         return $ONLINEIP;                 } if (getenv ("Http_client_ip") && strcasecmp (getenv ("Http_client_ip"), "unknown") {                 $onlineip = getenv ("Http_client_ip");         return $ONLINEIP;         } if (getenv ("Http_x_forwarded_for") && strcasecmp (getenv ("Http_x_forwarded_for"), "Unknown"))         {$onlineip = getenv ("Http_x_forwarded_for"); } return $ONLINEIP; }

Determine if an IP address

function Is_ip ($IP) {         $IP _array = Explode (".", $IP);         $IP _array_num = sizeof ($IP _array);         if ($IP _array_num! = 4)         {                 return FALSE;         }         $I = 0;         for (;    $I < $IP _array_num;    + + $I    )         {                 if (!is_numeric ($IP _array[$I]) && $IP _array[$I] < 0 | | 255 < $IP _array[$I]) 
  
   {                         return FALSE;                 }                 if (! ($I = = 3) &&! ($IP _array[$I] = = 255))                 {                         continue;                 }                 return FALSE;         }         return TRUE; }
  

Related articles:

PHP Verification of ID number correctness function

PHP ID Number Verification function

Three php form validation functions commonly used in project development

