Is it illegal to punch down in boxing when the other guy goes low to avoid your initial punch?

I never see this when I watch boxing matches so I was curious as to whether this was legal, illegal, maybe just rare or hard to pull off or what.|||no it is not illegal to punch down but it is illegal to hit on top of the head. some boxers will purposly dip that low so the other boxer can%26#039;t legally hit them which is also illigal. it is not rare and it is not hard to pull off. it happens in a lot of fights and is often the source of the controversy of when a boxer gets hit either on top of the head or in the back of the head.|||If you never seen this in boxing then you need to watch the 2nd fight between Margarito vs cintron. Margarito would throw non stop punches and instead of cintron clinching he would neal his upper body down and get hit behind his head. That happened a couple of times until cintron complained to the ref. I don%26#039;t think it should be illegal if while the punch is being thrown the opponent causes that by tililting down as the punch is being thrown. I don%26#039;t think it should be illegal if the other fighter throws the punch at the same time! I think the the other fighter should learn how to clinch!....?|||The second gentlemen who answered is correct. Punching down is okay, as long as you manage not to land anything on the back of the head, which could be somewhat difficult to do during the heat of battle.|||Not illegal as long as you don%26#039;t hit him in the back of the head. The rabbit punch is illegal and is hitting in the back of the head while erect.|||If you do that on purpose of course