Taking stock of "Are there any illegal bets in roulette?" takes in both halves of the table. A roulette table has two halves: the wheel, where a dealer spins the ball, and the board, where every bet is placed on a printed layout. The basic rules fit in a minute, yet the board holds dozens of bets with different payouts, and the dealer follows a fixed routine at every spin. Seeing how the board and the deal work answers most questions before a first chip goes down.
Roulette dealer rules keep every spin the same. The dealer spins the wheel one way and the ball the other, calls no more bets as the ball slows, marks the winning number with a dolly, clears losing chips first and pays winners from the outside in. Learning how to deal roulette means learning that routine and the payouts by heart. Board rules add limits on how chips may be stacked, so each bet can be read at a glance. Machines on the floor follow the same payouts and are not fixed. Regulations allow no illegal bets on the board.
Roulette is old: the wheel took its modern form in France in the late eighteenth century, and the single zero version spread from there. Wheels are not all the same today: European wheels have one zero, American wheels two, and double ball roulette drops two balls at once with its own payouts. Players can play roulette online on software wheels or live tables. Rules can change between casinos and tables, so the printed rules and limits come first. Licensed wheels are not rigged and balls are never weighted.