Ban

When a client is banned means that no one is going to upload or download files to/from client. In other words, a client which has been banned will just be ignored.

A client can be banned because of leeching or because it of potential damage to the network or client, such as Aggressive clients.

It is important to know the basic difference between a ban and a leeching. A banned client cannot upload nor download while a leecher doesn't upload but takes advantage of downloading.