The "fake player bug" described in short words is a type of vulnerability which is mainly located in multiplayer games without a real centralized authentication mechanism but, as demonstrated by my code, this problem can affect also other types of software on both UDP and TCP protocol and in some cases also those who have a cdkey validation system if such check is performed after having assigned the slot to the new player. The bug consists in the ability to use the main feature of a server, so letting clients to join it, in a Denial of Service through the filling of all its available players slots for a certain amount of time which varies due to the type of game and naturally the quality of the method used for exploiting this problem (which can be a stand-alone proof-of-concept or even the usage of multiple clients on the same machine). The main effect caused by such problem is that real clients/players can no longer join the server but sometimes exist also other problems like the impossibility of the server to handle too much clients (crash) and other negative effects dependent by the specific software (resource consumption, possibility to use spoofed packets and many others). Other than demostrating this vulnerability in different software, this section has also the secondary (and probably more interesting) purpose of showing the format of the protocols (sometimes more or less complex and basicly or fully implemented) used by their clients to join the servers, this is usually an incredible source of useful informations and real examples which often lead to other projects, documentations and/or bugs researching.