When you box must your weight be evenly distributed across your boxing stance to have balance or how does it work?
Your Basic stance, that you learn first in Boxing is with a balanced weight distribution of the legs.
But if you fight, the weight distribution changes and you need to learn punching and defending also in those situations. The weight distribution can also be more towards the front or towards the back foot.
Here is a nice article using the term axis to explain more in detail: http://www.expertboxing.com/boxing-strategy/counter-punching/the-3-axes-of-boxing