In online games, a list of player information (such as player ID or IP address) that the server checks for when admitting a player. By default, players are allowed to enter, but if they match information on the blacklist, they are barred from entry. The opposite is a whitelist, where the server bars players by default but allows players matching the whitelist. Blacklists and whitelists can be used in tandem, barring even whitelisted players if they try to log in via a blacklisted IP address, for example.
