Heres a list of some of the rcon commands for Call of Duty 4.
/serverinfo - This command shows the server settings and configurations.
/map [map name] - This will load the given map. Map names can be found in the map overview article here.
/map_rotate - This will load the next map of the rotation. This is set in the 'sv_maprotation' file on your server.
/map_restart - This will restart the current map.
/fast_restart - This will restart the current map just like /map_restart but is much faster as it will not load the map again. It will just restart the map.
/status - This shows information about the connected players. This includes the client ID, score, ping, GUID, name and IP address. The ID and name can be used for the following commands.
/tell [player id] - This will display a message to a specific player. The ID is given with the /status command.
/clientkick [player id] - This will kick a player according to its ID (given with the /status command).
/kick [player name] - This will do the same as the /clientkick command, but this command requires the player's name. However, some names are very difficult to enter (with colour codes etc.), thats why the /clientkick commands is easier in use. You can use 'all' as player name, this will kick all players from the server.
/onlykick [player name] - Does the same as /kick as far as I know.
/banClient [player id] - This command will ban a player according to its ID. The player's GUID will be added to ban.txt.
/banUser [player name] - This command does the same as the /banclient command. However, this requires you to fill in the player's name, it is therefore advised to use the /banclient command (names can be long or contain colour codes).
/tempBanClient [player id] - This will temporary ban a player using the player's ID. The length of a temporary ban can be changed in the server configuration file.
/tempBanUser [player name] - This will temporary ban a player using the player's name.
/unbanUser [player name] - This will unban a user according to the player's name. If the player's name appears more than once in ban.txt, you can edit the file and remove the banned player manually.
/dumpuser [player name] - This will give information about the player.
/killserver - As the name says, it will shut your server down.
It is very likely that you are not playing at the same location (IP address) as your server is. Thats where we use RCON (= remote control) commands for. Using RCON is very easy, just add '/rcon ' in front of the commands above (removing the '/' of those commands). But before you can use RCON, you will have to login:
/rcon login [password] - Fill in the password of the server and you can use RCON commands.
Examples of RCON commands:
/rcon map mp_pipeline
/rcon banclient 5