What are the rules for rushing the quarterback?

For your defense

• Up to two designated rushers per play, each starting at least 7 yards from the line of scrimmage (the rush line) at the snap.
• Rushers must raise a hand before the snap and rush immediately after it; delayed rushes aren't allowed. You're never required to rush.
• Players not rushing can defend the line of scrimmage but can't cross it until the ball is handed off, pitched, lateraled or passed.
• After a handoff, pitch or lateral, any defender may cross the line.
• Rushers can try to block a pass, but non-incidental contact with the QB is roughing the passer (+5 and first down).
• If the offense draws a rusher across the 7-yard marker before the snap, that rusher can't legally rush on that play.
• Illegal rush and encroachment: +5 from the line of scrimmage and first down for the offense.

For your offense

• You can't impede a rusher's path to the quarterback. The path is set before the snap, straight from the rusher to the QB, and doesn't move when the QB moves. A moving offensive player in that path must avoid the rusher; a player who stays still after the snap must be avoided by the rusher.
• Impeding the rusher: -5 and loss of down.
• A QB whose flag is pulled behind the line is sacked; in the offense's own end zone, it's a safety.