diff --git a/common/framework/ipfilter.php b/common/framework/ipfilter.php
new file mode 100644
index 000000000..b751b8d4b
--- /dev/null
+++ b/common/framework/ipfilter.php
@@ -0,0 +1,175 @@
+<?php
+
+namespace Rhymix\Framework;
+
+/**
+ * The IP filter class.
+ */
+class IpFilter
+{
+	/**
+	 * Check whether the given IP address belongs to a range.
+	 * 
+	 * @param string $ip
+	 * @param string $range
+	 * @return bool
+	 */
+	public static function inRange($ip, $range)
+	{
+		// Determine the type of the IP address.
+		if (preg_match('/[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$/', $ip, $matches))
+		{
+			$ip = $matches[0];
+			$ip_type = 4;
+		}
+		elseif (preg_match('/^[0-9a-f:]+$/i', $ip))
+		{
+			$ip = strtolower($ip);
+			$ip_type = 6;
+		}
+		
+		// Determine the type of the range.
+		if ($ip_type === 6 && strpos($range, ':') !== false)
+		{
+			$range_type = 'ipv6_cidr';
+		}
+		elseif ($ip_type === 4 && strpos($range, '*') !== false)
+		{
+			$range_type = 'ipv4_wildcard';
+		}
+		elseif ($ip_type === 4 && strpos($range, '-') !== false)
+		{
+			$range_type = 'ipv4_hyphen';
+		}
+		elseif ($ip_type === 4 && strpos($range, '.') !== false)
+		{
+			$range_type = 'ipv4_cidr';
+		}
+		else
+		{
+			$range_type = 'unknown';
+		}
+		
+		// Check!
+		switch ($range_type)
+		{
+			case 'ipv4_cidr':
+				return self::_checkIPv4CIDR($ip, $range);
+			case 'ipv6_cidr':
+				return self::_checkIPv6CIDR($ip, $range);
+			case 'ipv4_wildcard':
+				return self::_checkIPv4Wildcard($ip, $range);
+			case 'ipv4_hyphen':
+				return self::_checkIPv4Hyphen($ip, $range);
+			default:
+				return false;
+		}
+	}
+	
+	/**
+	 * Check whether a range definition is valid.
+	 * 
+	 * @param string $range
+	 * @return bool
+	 */
+	public static function validateRange($range)
+	{
+		$regexes = array(
+			'/^\d+\.\d+\.\d+\.\d+(\/\d+)?$/',
+			'/^\d+\.(\d+|\*)(\.(\d+|\*)(\.(\d+|\*))?)?$/',
+			'/^\d+\.\d+\.\d+\.\d+-\d+\.\d+\.\d+\.\d+$/',
+			'/^[0-9a-f:]+(\/\d+)?$/i',
+		);
+		
+		foreach ($regexes as $regex)
+		{
+			if (preg_match($regex, $range))
+			{
+				return true;
+			}
+		}
+		return false;
+	}
+	
+	/**
+	 * Check whether the given IPv4 address belongs to a IPv4 CIDR range with mask.
+	 * 
+	 * Example: 172.16.0.0/12
+	 * 
+	 * @param string $ip
+	 * @param string $range
+	 * @return bool
+	 */
+	protected static function _checkIPv4CIDR($ip, $range)
+	{
+		if (strpos($range, '/') === false) $range .= '/32';
+		list($range, $mask) = explode('/', $range);
+		$ip = ip2long($ip) & (0xffffffff << (32 - $mask));
+		$range = ip2long($range) & (0xffffffff << (32 - $mask));
+		return $ip === $range;
+	}
+	
+	/**
+	 * Check whether the given IPv4 address belongs to a IPv6 CIDR range with mask.
+	 * 
+	 * Example: 2400:cb00::/32
+	 * 
+	 * @param string $ip
+	 * @param string $range
+	 * @return bool
+	 */
+	protected static function _checkIPv6CIDR($ip, $range)
+	{
+		if (function_exists('inet_pton'))
+		{
+			if (strpos($range, '/') === false) $range .= '/128';
+			list($range, $mask) = explode('/', $range);
+			$ip = substr(bin2hex(inet_pton($ip)), 0, intval($mask / 4));
+			$range = substr(bin2hex(inet_pton($range)), 0, intval($mask / 4));
+			return $ip === $range;
+		}
+		else
+		{
+			return false;
+		}
+	}
+	
+	/**
+	 * Check whether the given IPv4 address belongs to a IPv4 wildcard range.
+	 * 
+	 * Example: 192.168.*.*
+	 * 
+	 * @param string $ip
+	 * @param string $range
+	 * @return bool
+	 */
+	protected static function _checkIPv4Wildcard($ip, $range)
+	{
+		$count = count(explode('.', $range));
+		if ($count < 4)
+		{
+			$range .= str_repeat('.*', 4 - $count);
+		}
+		$range = str_replace(array('.', '*'), array('\\.', '\\d+'), trim($range));
+		var_dump($ip, $range);
+		return preg_match("/^$range$/", $ip) ? true : false;
+	}
+	
+	/**
+	 * Check whether the given IPv4 address belongs to a IPv4 hyphen range.
+	 * 
+	 * Example: 192.168.0.0-192.168.255.255
+	 * 
+	 * @param string $ip
+	 * @param string $range
+	 * @return bool
+	 */
+	protected static function _checkIPv4Hyphen($ip, $range)
+	{
+		$ip = sprintf('%u', ip2long($ip));
+		list($range_start, $range_end) = explode('-', $range);
+		$range_start = sprintf('%u', ip2long(trim($range_start)));
+		$range_end = sprintf('%u', ip2long(trim($range_end)));
+		return ($ip >= $range_start && $ip <= $range_end);
+	}
+}