It will only be set if you're running the script through a webserver. If you're running PHP in CLI (command line) mode, REMOTE_ADDR will not be set, as there is no remote address for a command line script.
$_SERVER['REMOTE_ADDR'] is always set even if you are working on localhost and can't be unset except you programmatically removed it And if you saved it in INT there would be no dots so you should save it as varchar