In volleyball, there are specific rules regarding blocking and attacking a serve. According to the answer, a player is not allowed to block or attack a serve from "on or inside the 10-foot line." The 10-foot line, also known as the attack line or the three-meter line, is a boundary on the volleyball court that is located 10 feet away from the net. This line marks the area where front-line players are restricted from making certain offensive actions. When a player is positioned on or inside the 10-foot line, they are not allowed to block or attack the serve. Blocking refers to when a player attempts to stop the ball from crossing the net by jumping and extending their arms above the net. Attacking, on the other hand, refers to an offensive action where a player tries to hit the ball forcefully into the opponent's court. However, it is important to note that once the serve is made and the ball crosses the net, front-line players are allowed to switch positions at the net. This means they can move to different areas on their side of the court, as long as they do not cross the centerline. Overall, the main idea is that players positioned on or inside the 10-foot line cannot block or attack the serve, but they can adjust their positions after the serve has been made.