+// Checks whether given address is IPv4
+function isIp4AddressValid ($address) {
+ // Is there cache?
+ if (!isset($GLOBALS[__FUNCTION__][$address])) {
+ // Determine it ...
+ $GLOBALS[__FUNCTION__][$address] = preg_match('/((25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9]))/', $address);
+ } // END - if
+
+ // Return cache
+ return $GLOBALS[__FUNCTION__][$address];
+}
+