As technology has been developed, the network of bot, botnet, has been huge matter in computer science society. Most botnet causes network security threats and they are based on C&C server such as IRC, HTTP common protocol [1] and recently botnet also constructs P2P connection and the bot’s characteristics and activities are all different according to the structure of botnet. That is why the existed research is numerous, too, and it is beneficial to category and to classify defense mechanism of bot. The bot activities result in a lot of negative effects such as DDoS (Distributed Denial of Service) and Spamming. The mechanisms for bot detection and defenses can be categorized into C&C based bot detection and P2P based bot detection. Besides, theses mechanisms recently can be combined algorithms from different studies. Several DDoS defense methods also will be introduced in this paper. In this survey paper, recent mechanisms for defense of botnet will be introduced and stressed.