The ban console command will disconnect the specified player from the server and disallow connections from their IP address by default for 20 minutes, but possibly shorter or longer times depending on custom server settings. To warn a player for bad behaviour, you can use the kick command beforehand, and ban if the player continues his/her disruptive behaviour. Note, however, that being banned is not the same thing as being blacklisted.
With the default configuration, banning is restricted to admins only, but it can be enabled for normal players by using the -b switch in the
servercmdline.txt. Players who team kill too much may be automatically banned.
Possible screen messages
ExamplePlayer1 called a vote: ban player ExamplePlayer2 could not vote: no permission
ExamplePlayer1 called a vote: ban player ExamplePlayer2 invalid reason