new slotUsed[ MAX_PLAYERS char ];
new playersIP[ MAX_PLAYERS ][ 64 ];

public OnPlayerConnect( playerid ) {
     new __IP[ 64 ];
     GetPlayerIp( playerid, __IP, 64 );
     if ( slotUsed{ playerid } && !strcmp( playersIP[ playerid ], __IP, true ) ) {
         return Ban( playerid ); // Наказали игрока
     }
     GetPlayerIp( playerid, playersIP[ playerid ], 64 );
     slotUsed{ playerid } = 1;
     return true;
}

public OnPlayerDisconnect( playerid, reason ) {
     slotUsed{ playerid } = 0;
     return true;
}