Volleyball rules state that players rotate clockwise each time service is won and remain there until it is gained back from the opposition. Beginning with the server in the back-right corner, players are designated positions one through six in a counter-clockwise rotation, with each position representing respective "zones" one through six.
Although players are not restricted to their zone during a volley, they all must be wary of their position on the court each time the ball is contacted at the serve. Those out of position relative to their teammates' zones are subject to a player "out of alignment" fault, also known as a "position overlap."
For example, player five must always be positioned behind player four (directly in front of him) and to the left of player six (to his right), measured by the placement of his feet on the court. If one foot of player five is closer to the net than those of player four or the feet of player six are closer to the sideline of player five's left, an overlap violation results in a point for the opposing team and loss of service, if his team was serving.
Additionally, the three front row players - two, three and four - are the designated attackers. Although back row players five, six and one may hit the ball, both feet must be behind the 10-foot attack line designated on the court when initiating the attempt.