There is not. That's one thing we've noted is lacking with transfers, is that the destination server can't tell that the player was transferred.
very possible you can save transfer X player to Y server but it only work IF you own both server you cannot tell if some server you dont own transfered their player to you
I want that the players only can join over my main server. How can I check this? If I only write this to a database the players could join over it, leave and join another server. But I want to block that
PHP: Mainserver:onRequestJoin2ndServer:$player//$db should be some sort of database where both servers shares$db->insert($player,time());$player->transfer(2ndServer);2ndServer:onJoin:$player //i think there's better events for that usage, you should also set lowest priority$time =$db->read($player);if ($time == false){//not set yet$ev->setCancelled();$this->kickTask($player,'Please join via the main server');//using task because last time i tried there's a weird crash bug if you kick them before they joined maybe cancelled ev helps} elseif (time() - $time > 120){$ev->setCancelled();$this->kickTask($player,'Please join again via the main server\n(Transfer timeout)');$db->drop($player);} else {$db->drop($player);$this->welcome($player);}