I have the phpbb3 arcade mod installed on my forum and there's a session ID on the games (different url each time the page is loaded), so each game is getting indexed many many times. This is bad because it's duplicated content and I need to get rid of it. An example url with session ID is: www. thearchived .com/forum/viewgame.php?g=21&u=57&action=vi=... The actual game is: www.thearchived.com/forum/viewgame.php?g=21 Can i use robots.txt to block the session ID? How would I do it?