This type of attack threatens client-to-client systems where communication is not through the server but directly between users. This is typically a network where users share large amounts of data. Currently, peer-to-peer networks are practically retreating and are typically used only for the illegal distribution of content, mostly multimedia. The principle of such an attack is to misuse a client application (such as DC ++) to disrupt an existing connection and attempt to connect to the victim. In case the attack is well executed, the victim may be exposed to a multitude of hundreds of requests for connection. This type of attack can be relatively easy to filter, but in a massive attack, the filtration itself can result in system crashes. The attacker does not have to communicate directly with the client to reach his/her goal. Moreover, automated P2P-enabled processes make it possible to intensify the attack, with the unintentional consent of the victim.