1. <?php
  2. /**
  3.  * is_ipaddr() Function
  4.  * Created by: Joshua H. (TRUSTAbyss)
  5.  *
  6.  * This function returns a boolean value.
  7.  * Usage: is_ipaddr("IP");
  8.  */
  9.  
  10. function is_ipaddr($ip)
  11. {
  12. 	$result = FALSE;
  13.  
  14. 	// Check to see if the IP Address is valid.
  15. 	if (preg_match("/^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$/", $ip, $matches))
  16. 	{
  17. 		// Check each of the IP digits to see if they're less than or equal to 255 (valid IP Range). 
  18. 		if (($matches[1] <= 255) && ($matches[2] <= 255) && ($matches[3] <= 255) && ($matches[4] <= 255))
  19. 		{
  20. 			$result = TRUE; // Valid IP.
  21. 		}
  22. 	}
  23.  
  24. 	return $result;
  25. }
  26.  
  27. // Example code below.
  28.  
  29. if (is_ipaddr("65.5.240.229"))
  30. {
  31. 	echo "This is a valid IP Address. ";
  32.  
  33. }
  34. else
  35. {
  36. 	echo "This is NOT a valid IP Address.";
  37. }
  38. ?>