In this paper we released some connection problems with BitTorrent (BT) that we have founded in our four months' experimental study. One connection per IP address is usually used by network application software for flow fairness. However if one connection per IP address is configured with BT there will be some problems in connection setup, which induces some peers not to find some of others even the number of total peers is small. These problems are caused by some bugs in the current BT. All of these problems will be detailed in this paper and modified source codes are also given. We hope this work be helpful for some researchers' experimental study, perfect BT's real use, and arouse similar project's attention to these connection problems.